Studentaid.gov IBR vs standard calculator

I have pre-2014 consolidated graduate loans, both unsubsidized and subsidized. I was on old IBR from 2013-2023, and then on SAVE from 2024 until it was halted. I have around 140 months in qualifying payments. I’ve been in SAVE since then using the funds to pay for other things. My income is finally high enough that I can conceivably pay down the balance. When I run the studentaid.gov calculator, it has my IBR calculation at $1300/month and standard at $1100/month (I have large professional school balances). But I don’t understand how the standard is only $1100 and not $1700/month with the loan balance of $157k. Is standard on graduate consolidated loans calculated based on 30 year repayment or based on the balance when I started IBR? Or is the calculator just wrong?