Purchase control vs. PSA and accounting system for MSPs

These are the key points

• A PSA manages tickets, hours, assets and SLAs. It is not built for supplier invoice checking or per-customer purchasing connection.
• An accounting system records and books whatever comes in. It does not check the substance of whether supplier invoices are correct.
• Purchasing control compares supplier invoices in substance against contracts, usage and customer profiles. That is what the other two systems do not do.
• The three systems are complementary: each has its own function and they reinforce one another when they are fed properly.
• Purchasing control is the link that ensures your PSA and accounting system are fed with reliable, substantively checked purchasing data.

In this article, we cover the following topics:

• The misconception that costs MSPs money
• What a PSA does and does not do
• What an accounting system does and does not do
• What purchasing control does that the other two do not
• How the three systems work together as a complementary whole
• The comparison at a glance
• Frequently asked questions

The misconception that costs MSPs money

Many MSPs believe their purchasing is well in hand because they use a PSA and their invoices are in the accounts. That conviction sounds logical: the PSA records contracts, hours and services per customer. The accounts process the supplier invoices. Together, surely they should provide enough control?

In practice they both miss the same thing: the substantive check of what the supplier invoices against what was agreed, ordered and delivered. A PSA records that customer A has a Microsoft 365 subscription. But does it compare the Microsoft purchase invoice with that subscription? No. An accounting system books the invoice from Dstny. But does it check whether the invoiced usage matches the active services per customer? No. That gap is exactly where margin leaks arise and exactly where purchasing control proves its worth as a third layer.

What a PSA does and does not do

A PSA (Professional Services Automation) is built to automate the operational side of an MSP. Systems such as HaloPSA, Autotask and ConnectWise Manage cover the following core functions: ticket management and service desk, SLA management, hours and time tracking, asset management, contract management and project management. The PSA ensures your team knows which customer takes which services, which tickets are open and how many hours have been logged. That is indispensable for any MSP serving multiple customers.

What a PSA structurally does not do:

• Compare supplier invoices in substance against contract terms
• Flag rate discrepancies or volume errors in purchase invoices
• Link purchasing costs per customer to supplier invoice lines
• Process CDR data together with the corresponding call, SMS or data bundle.
• Automatically alert you when a cancelled service is still being invoiced

What an accounting system does and does not do

An accounting system such as Exact Online, Twinfield or AFAS is built for financial administration and reporting. Core functions are: invoice registration (purchasing and sales), accounts receivable and accounts payable administration, VAT returns, general ledger entries, annual accounts and financial reporting.

An accounting system is where everything lands. Purchase invoices are booked as costs, sales invoices as revenue, payments are processed and the balance sheet adds up at the end of the year. That is the function of the accounts: accurate financial registration.

What an accounting system structurally does not do:

• Check whether a supplier invoice matches the contract terms in substance
• Break down purchasing costs per end customer
• Flag that an invoice line relates to a service that has already been cancelled
• Compare what you purchased with what you passed on per customer
• Provide a margin overview per customer, per service or per supplier

Accounting records reality after the fact. If a supplier invoice is incorrect or purchasing costs are not allocated per customer, accounting simply processes it. It does not flag the error; it just records it.

What purchasing control does that the others do not

Purchasing control fills the gap between the PSA and the accounts. It is the layer that actively checks what comes in on the purchasing side and compares it with what has been agreed contractually and recorded per customer. In concrete terms, purchasing control does the following, which the PSA and accounts do not:

• Substantive invoice checking: every purchase invoice is compared with the contract terms, the agreed rate and the active services per customer. Discrepancies are flagged immediately.
• Per-customer purchasing connection: purchasing costs are automatically linked to the corresponding customer profile. That makes the cost price per customer visible and the cost allocation traceable.
• Proactive discrepancy alerts: before the customer invoice goes out, it is visible whether there are any discrepancies. Not afterwards at the month-end close, but at the moment the invoice is received.
• Margin overview per customer and service: purchasing data and sales data are placed side by side. You see the actual margin per customer, per service and per supplier.

Want to know more about the specific discrepancies that purchasing control uncovers? Then also read how you detect discrepancies in supplier invoices as a structural part of your operation.

How the three systems work together as a complementary whole

The strongest MSP administration combines all three layers. Each system has its own role and feeds the next system with more reliable data.

The PSA is the operational layer: it records which services are active per customer, what has been ordered and which tickets are open. That information is the input for purchasing control: which services are expected per customer on the purchase invoice?

Purchasing control is the verification layer: it imports the purchase invoice, compares it with the PSA data and contract terms, detects discrepancies and links checked purchasing costs per customer. That checked purchasing data is the input for the accounts: accurate, traceable costs per customer that can be booked.

The accounts are the registration layer: they process what has been approved after purchasing control. The annual accounts, the VAT return and the financial reporting are correct because the data was already checked beforehand.

InkoopControle by ResalePartners is built specifically as that verification layer. It connects with PSA tools such as Autotask and HaloPSA for customer data and links to accounting systems such as Exact Online for the bookings. The PSA and the accounts stay in place, but are fed more reliably. Want to know too how purchasing costs are linked per customer as the foundation for that verification layer? And how 110+ suppliers are connected to make the purchasing data automatically available? 

The comparison at a glance

Want to see how purchasing control complements your PSA and accounts?

Book a free demo of InkoopControle and discover in 30 minutes what the verification layer looks like alongside your existing systems. Your PSA and accounting system stay in place, but are fed more reliably.

View the full purchasing control for MSPs