Commissions are a critical component of your compensation, yet you are forced to rely on blind faith and trust that your pay is correct.
Deal was classified in the wrong category, resulting in a lower commission rate. For example, a salesperson had a large customer that was coming off a 3 year, $1 million managed service contract for help desk support. The customer informed the company that they were not renewing the arrangement and were moving forward in a different direction. After several months of hard work, the salesperson was able to sell a new contract to the existing customer, with new terms, new services and a reduction in scope.
A new salesperson joins a company and inherits several existing "house" accounts that previously belonged to a former salesperson who left the company. Several months into the new person's tenure, there are additional costs, product returns, and a reduction in the scope of the original engagement that the previous salesperson sold. The employer attempted to charge back to the new salesperson the credits associated with the earnings from the previous salesperson.
On occasion a sales manager will decide to split the commission on a new customer deal between two sales people, but have one salesperson own the account moving forward and receive full YTD quota credit for the deal.
Accounting department mistakenly didn't invoice the customer, so no commission was paid. This kind of error is not uncommon, especially when inter-departmental communication is required to successfully complete the deal lifecycle. Whether you are paid on invoicing or paid on revenue, these kinds of errors can negatively impact earnings.
Sometimes there are errors made by the salesperson's support team in configuring a quote, missing cables, omissions, wrong pricing, etc., and at times after the deal has been booked, these additional costs are tacked on the salespersons deal and reduces gross profit and commissions, often without the salesperson's knowledge or approval.
Vendors will offer rebates paid after the deal closes on specific products. This allows the salesperson to be more aggressive on pricing knowing that there will be rebate dollars coming after the deal to make up for it. If a salesperson does not track it, a company can overlook it at times and not allocate it back to the salesperson.