Work with lower reps then.
Imagine this: You train with 225 and continue to train. Every couple of weeks or so you squeak out one more rep. You add reps to 225, but have never attempted to lift anything higher than 225. You may eventually get strong enough to hit 225 ten times, but you will probably get crushed by anything over 250.
I'm not saying this is you, but I'm trying to stress the importance of using heavier weights and lower-rep sets.
Yes, most 1RM charts put 225 for 10 as a 300 1RM, but that is just a general guide. It may or may not apply to you.
So, after all that, my point is to use heavier weights, too, in lower-rep sets. Try some sets of 5 or 3 or even some sets of singles around 90-95% of your max.
Hope I made sense without rambling too much,