Add +2.00 has a working distance for the nearby of 50 cm or nearly 20
inches. (50/2.54=19.69)

To become a 15 inches in the above you need almost  +2.75.

All the above with the eyes not accommodating and assuming your distance
power is correct measured and  placed in the frame.

My advise?

Have your eyes and your glasses checked!

Changing to +175 is probably such a small change it's not worthwhile. I'd
suggest +150 if you really feel the +200 is focussed too close.

There are formulas and rules of thumb for calculating the bifocal add, but
the ultimate and most accurate answer comes from trialling the lens power in
a trial frame and checking the focal range for yourself - this can easily be
done during the eye test.

Unless you are using them as industrial safety specs, a high index optical
plastic is probably going to give you better quality of vision than
polycarbonate.

Dom