Had a listen to the first video this morning. You are pulling some great sounds out of the PX.
I agree with Derek - I especially liked the Wavestation pad, and inspires me to try this and some of the other techniques you showed.
None of these are 1:1 copies of the original patches, they are intended to be inspired by them but have their own unique flavor. I think they certainly show that using the linear arithmetic synthesis and additive synthesis techniques you can achieve some pretty fantastic sounds.