Here is something I found that might give you a clue. Found this on the travel.state.gov FAQ:
If the poverty guidelines change between the time the petitioner signed the Affidavit of Support and the issuance of an immigrant visa, must the petitioner/sponsor and joint sponsor, if required, submit a new Form I-864?
No, the Form I-864 remains valid indefinitely unless evidence of failure to meet the poverty guidelines in effect on the date of I-864 filing arises. The consular officer will determine whether the income claimed by the sponsor and documented with financial evidence meets the poverty guidelines in effect at the time the I-864 was filed. If the income claimed does not meet the poverty guidelines, then the consular officer may request that the sponsor submit current year income information.
I would send copies of your transcripts and last few paystubs just in case, but your husband shouldn't volunteer the documents during the interview if not asked.