Hi kxk - welcome to Pherotalk. 
The MXs are likely part of the stealth diffusion tests that AD are running just now. Most are TAA-based, which is a main component of Instant Shine, so the effects are similar. Some MXs have been done with P130, which again is a comforting, relaxing phero that has produced hits from scary-young women for me. They should both be usable at work. However I will say now that I don’t find A314/IO a good mix but A314/IS is excellent and IS/IO is a great social mix that is also good with TUTH in more raunchy environments (clubs etc). However, if a mix works for you, fine!
The Idea is that AD would like you to test them on their own, then put your results in the dedicated threads in the MX Tests subforum. Once you have an idea of how they work for you, they can both be used alongside other pheros and IME both go pretty well with a good range of products.
To answer your question, all spray pheros can be layered over each other. simply spray and leave a couple of minutes between each layer to let them dry down. The only thing you need to avoid is spraying over oil-base (and vice versa) as this will wreck diffusion.
For app points, have a read of this:
Don’t get too hung-up on them though - so long as a spot has a good blood flow to help diffusion and is open enough to diffuse, its a usable app point.