That is a good tapering schedule, and he will probably start you on the lexapro while you are still on the lower dose of zoloft.
That taper sounds correct. I was on Lexapro for a few year and I tapered the same way. Lexapro takes about 2-6 weeks to take full effect so you may want to ask your doc about that time between. You will have something in your system though so I think most likely you will be ok.
GOOD LUCK
It sounds like your doctor knows what he's doing. Yes that's a good tapering off method. However, you may experience some inevitable anxiety. You may want to ask for a presciption for a kalonopin or xanax while you are making the switch.