NFL Blackout

We receive 2 FOX channels here in Salisbury MD, our local affiliate FOX 21,and also WTTG from Washington DC. On the occasions that those affiliates are NOT carrying the same games (like today - Giants and Eagles on FOX 21,Washington and Detroit on WTTG), the DC affiliate is STILL blocked out. Why?? They are airing different programming and in paying to have both affiliates available to me. Can this be corrected? I