I've recently realized I've been bench pressing incorrectly for the past 4 years or so. Recently I've improved my form dramatically. I went from barely having an arch, very little leg drive, way too large of an angle between my upper arm and torso, and the bar landing way to high up on my chest to much more proper form. I've worked on the arch, adjusted my feet to add some leg drive, decreased the angle between my arm and torso, and now touch my chest every rep. I used to stop about an inch or two before touching my chest with the old form, simply because at the arm angle I was using, it felt really awkward and painful to go any lower. The bar would have touched a little higher than the middle of my pecs, now it touches right at the bottom of my pecs.
The form "feels" good, but I'm significantly weaker performing the bench press this way. My 5 rep max was 275 lbs the old way, now it's about 225 lbs, even with the new much shorter range of motion. Even though I'm going all the way down to touch my chest, I've also really been focusing on driving my shoulders back into the bench and maintaining a higher arch to shorten the ROM.
My question is should this strength loss be expected due to the many changes I've made to the form I've been using for years? I'm guessing my neglect for the very bottom of the ROM has left me with a huge weak point in my lift. Also, any really rough estimates how long it might take to get comfortable with this new form and start making some nice strength gains again?
Thanks in advance