Received retired pay slip, but signed to receive 90% VA payments

I am just really confused as my husband is a 90% VA, 70% DOD and was in for five years and nine months.

He signed and spoke with the VA on the phone and will receive payments from the VA about $2500, however, we just got a paper in the mail that says that he is going to receive monthly retired pay in the amount of $1947.

I’m not really sure what’s happening, and thought that they couldn’t be received concurrent because he didn’t retire after 20 years.

He was actually on his last day that he would not be receiving retirement pay.