Mortgage "What if" tool isn't working

Question

I'm running Quicken Deluxe R38.30 and trying to use the "What if" tool to estimate what extra mortgage principal payments might do for me but it seems broken.

My outstanding principal balance is roughly $500k and entering an extra principal of $1000/mo only reduces the loan lifetime by 1 month. Even $10k/mo only reduces it by 10 months and a ridiculous number like $100k/mo only reduces the lifetime by ~7 years (on a loan with a good 29 years left).

If I use the What If tool on my auto loan for paying extra principle it looks much more reasonable.

Did I maybe set something up wrong? Is this a known issue? Or is it working properly and I've completely missed something.

Boatnmaniac · Answer

It does sound like perhaps your data file has some corruption in it.  Before you go through the effort of recreating your accounts you might want to run Validate and Repair (File > Validate and Repair file).  V&R can not only fix some data file issues but it can also fix some app issues.  When V&R is completed, check out the What If tool to see if the issue is resolved.

CodingHero · Answer

I tried both options and the calculation result is the same (time wise; dollar wise it's not exactly the same but pretty close). I made a new file with a test house and mortgage and the tool works. So maybe I just need to recreate my accounts.

Boatnmaniac · Answer

I suspect that when you used the "What if" tool you entered the additional monthly principal payments into the part of the tool that is used for making a 1X payment...or you tic'd that instead of the monthly payments option.  When I did that I got the same results as you did.  But when I used and tic'd the monthly payments option the results I got 100% matched an online calculator I found and were what I had expected.
Make sure you put the monthly additional principal amount in the part of the tool for monthly payments...and tic it...and you should get accurate results.