The options for Rows per page are:
[1] = 10,
[2] = 25,
[3] = 50,
[4] = 100,
When Rows per page is set to 10, it shows 1 result. When set to 25, it shows 2 results. When set to 50, it shows 3 results and so on. The same is true when you hit the Payments API directly.
Expected behavior
Setting Rows per page to 10, 25, 50, or 100 would show that amount of transactions per page.
Page URL: https://create.roblox.com/dashboard/transactions?paymentType=IncomingPayments