3801 Payment HELP // im confused

I received a payment of $853 from "38010000000 FED PAYMNT"

After googling it, its from a PCS/Travel pay or reimbursement. I am confused b/c on my TMO PPM move pay form for my PCS, it says I will be receiving $1,799 (before federal taxes, but taxes won't take it down to $853… right?). My eFinance voucher I am only supposed to be receiving $283 for my plane ticket to get here in Virginia from Vandenberg. My LES does not say anything different other than the extra BAS reimbursements (a negative deduction of $786 that I am receiving b/c it just started for me.)

So my question is what is this money from? Did they overpay me? Do they split the TMO PPM pay in half and give it at EOM and Mid month? Or is this from my travel voucher (but again, only supposed to be getting $283)? someone HELP