Incorrect property value used as basis for mediation

I was asked by attorney to declare value of properties. i had one appraised and used tax value for others.
They went with tax value (mine) but i found out later that husband had called a realtor and was given a much lower estimate for the property though it was not declared on a sheet. I never saw what his attorney asked and suspect it was not given, that they just used my higher tax value.
I ended up with the property and he now gets cash equal to this tax value with is 23K to 33K more than the husband found out (but was never revealed to me) was the estimated current value. I have info from appraisals that husband’s lower-valuation info is correct.
Can I protest this tho i signed mediation and divorce is final?

No, the agreement is final, and they did not have to disclose an appraisal with a lower value.