First week back to work - will he eat less eventually?

So much for worrying about him taking the bottle - he's PIGGING out. I'm VERY hard pressed to keep up with his demand and I think I'm pumping a LOT! He's eating between 14-19 ounces a day this first week! 14 being just one day - the other days it was 18-19 ounces. I'm managing to pump between 16-18 ounces, but that's with 4 sessions a day. Thankfully my work is being VERY generous on pumping time - they're letting me take as many breaks as I need ON the clock - but I can't keep 4 sessions up forever. I'm eating oatmeal, drinking Mother's Milk tea, pumping extra after the first morning feeding - everything I can think of for maximum supply. My Mom is watching him while I work and she's trying to hold him off as long as possible, but he's VERY impatient when hungry. I feed him at 7 just as I'm leaving her house and he's already wanting a bottle around 8 - no matter how much I feed him. Then another around 10, one at 12:30 and then 2:30-3 or so. I'm leaving him 4 oz per bottle, but sometimes she has to heat another 2 oz or so from the frozen stash I left her (nearly 40 oz frozen in 2oz increments). He eats as soon as I get home (4:15 or so) for nearly an hour and then every hour on the hour until bedtime. He goes down around 9pm and wakes up at 2am and 5am to eat. Will he eventually slow down as he gets more comfortable? Or will my supply eventually increase even more? Or will I get more per pumping and be able to pump less often at some point in the future? I always thought EBF babies generally ate between 8-12 ounces while away from their Moms for a 8 hour workday so this is really suprising me! The other day he took 19 ounces during the day and STILL ate 7 FULL time while I had him - how much is this kiddo consuming? No wonder he went from a petite 5 pounds, 10 ounces at birth to over 13 pounds now at 11 weeks! Reassurance please!