There is $300 credit limit on the account unlike in the past. you can make multiple payments of $175 until your last payment pushes the credit balance over $300.
If you are currently sitting on a bill of $51 or greater, you can apply up to three payments of $175 before hitting the limit. Broken down, $-51+$175+$175 = $299 so you can squeeze in a third payment of $175 which will leave you with a balance of $474 credit.