Underestimating income

[Pandora]

Yours will impact ftb b
His will impact ftb a

If you know your estimates and actuals, check out the online estimator

ETA
I re read your post. So to be clear,
You overestimated 1 month by 10k
You underestimated 11 months by $500 per month?

That would mean you overestimated by $4500 all up? So you should be fine in that case??