Your monthly processing statement: how to read it in ten minutes
Most merchants look at one number on this document. Here are the four sections that actually matter, and what Canadian rules let you insist on.

Your monthly processing statement arrives, you look at the total fees, you sigh, and you file it. That is roughly what everyone does.
The trouble is that this document is one of the few places you can see whether something changed without anyone telling you. Ten minutes a month is enough. Here is what to look at, in order.
One: gross sales versus net deposits
The statement normally opens with processed volume: the total your customers paid. That is not what reached your account.
In between sit the fees, the refunds you issued, and adjustments: disputes, corrections, reversals. The first check is arithmetic: gross volume minus deductions should match the deposits that landed in your bank account during the period.
If it doesn't line up, that isn't necessarily an error. A batch closed on the last night of the month can be deposited in the following one, so it shows up in one period and not the other. Rule that out before you pick up the phone.
Two: per-transaction fees versus monthly fees
These two families behave very differently and should be read separately.
Per-transaction fees rise and fall with your sales. A busier month costs more, and that is normal. What to watch is the average cost per transaction rather than the total.
Monthly fees don't move with activity: service fees, compliance-related fees, equipment rental, statement fees, inactive account fees. This is where changes hide, because a fixed amount doesn't stand out in a busy month.
The most effective method is also the dumbest: keep last month's statement beside this one and compare the fixed-fee lists line by line. A new line, a changed amount, a reworded label: it takes a minute to spot.
Three: the effective merchant discount rate
This is the most useful figure on the document, and the one merchants look at least.
In Canada, the Code of Conduct for the Payment Card Industry in Canada, overseen by the Financial Consumer Agency of Canada, provides that merchants receive, or have access to, a monthly statement showing the effective merchant discount rate for each card type, along with the rate and total amount charged for the various fees.
The effective merchant discount rate is calculated by dividing the total fees paid for a given card type by the sales volume for that card type. In plain terms: what a sale on that card actually costs you, all in.
Tracked month over month, it tells a story the fee total doesn't. If it climbs while your agreement hasn't changed, it is almost always because your payment mix changed: more rewards cards, more keyed-in transactions, more online sales.
Write each month's effective rate into a simple table. Twelve numbers in a row will teach you more than any conversation about pricing.
Four: adjustments and disputes
This section is short, usually near the end, and the most urgent to read. A dispute shows up here whether or not you noticed the notice, and response windows are tight.
Check as well that every refund listed corresponds to a refund you actually authorized. It is one of the few simple internal controls you have over what happens at the counter.
What the Code of Conduct lets you insist on
The Code provides that information given to you be clear, simple and not misleading, and that merchant agreements and statements for card processing carry enough detail, be readily available and be easy to understand.
It also frames how changes to fees must be communicated and what rights follow for the merchant. If your statement is unreadable, or fees appear with no explanation, that is not something you have to live with. It is a question to ask, and the Financial Consumer Agency of Canada publishes merchant rights on its site.
Concretely, this month: pull the last two statements, compare the fixed fees line by line, record the effective rate in a table, and have any line you don't understand explained in writing. You do not have to settle for a verbal answer.