Late-Night Bench-Press

I went to the gym to do some late night benching and some chins.  I benched 3 sets of 225x5.  I got them all up, but it felt harder than I think it should have.  I haven't done sets across in some time now.  I also haven't done sets of 5 for work sets, either.  And it was after midnight.  Whatever the cause, my bench felt weak.  I am glad I am going back to an A/B workout regimen--Benching and Pressing three times every 14 days will hopefully bring my upper-body strength back up.