It depends how it is added. RS Powders are steeped in the stuff so it is very equally distributed. I cant see how it would be unstable, it is certainly less spikey and more forgiving, seeing a lot of use in CSR for heavier bullets.
The only downside with any DB powder might be slightly accellerated throat wear and cracking but we will get that regardless because of rapid 10 shot strings with little cooling I am afraid.
IF it is slightly temp unstable, which I was told it wasnt, in normal British weather we probably would not notice.
I'm a maggot in another life you know