Hello again,
Well you have every right to perform crappy calculations as much as you see fit 
(ha ha, just kidding there).
The main point is if it works and you are happy with the results, then what the heck, use it.
I'm not trying to tell you how to do this, just suggesting some things, and originally it looked like you were using Taylor's so i through i would add a little information here.
You might also be familiar with the technique of generating a sine synthesis for PWM. That involves the solutions to the intersections of a triangle and a sine wave. The triangle is at a fairly high multiple of the sine so it 'picks out' time portions of the sine. Those portions are then the PWM pulse length for that average time position.
There are a lot of ways of doing these things so i guess i thought you would like to discuss them. Some are better than others, and some are faster than others, but if you have something that works for you that's great too no matter how it compares to other methods.
I wish you all the luck with it.