Going from 150mg to 300mg XL jump

So I was taking 150mg, which was 75mg IR twice. I'd take one just when I wake up and then the other before noon. My dr. just put me on XL, and he wants me to do 150mg for one week and then jump up to 300mg.

Personally, I'm a little worried about a big jump that quickly. The 150mg is the same so it's no jump at all, but then 150mg more. I'm wondering if it's a horrible idea to take the 150mg XL and one 75mg IR in the morning at first for a week, and then stop the IR when I'm at 300mg XL?