Nice to know, Im just a step behind you, that is nice for me thanks, Im just finish a quad update from Apm with a pixracer, Im going to check that param just in case 
I tried the pixracer R15 as well and had nothing but troubles with it, ended up switching to the cube and mini carrier board and it works 100% better.
I have ordered a Pix Mini for my large quad to swap out the Pixracer.
I still have a rcer on my test machine and so far it’s working ok but if it crashed, well it would be sad but not the end of the world. My 1.2m quad however…well that would be bad.
Several batches of Pixracers that I purchased from www.Thanksbuyer.com arrived with poor quality soldering of the barometric pressure sensors. Some failed instantly. Others failed sporadically during flight. I removed the sensor and replaced with a new sensor correcting the fault.