Tested.
TinyPhreak from wowhead did a good job, tested all the spells, wrote the timers and update all info to 5.4.8. patch.
Wow, someone create guide without proof, where calculations, timers about stacking... Lol. And do you trust him more?)
10%+15%=25% - that’s additive stacking.
With multiplicative stacking - (0,85*0,9)=0,765=76,5%; 100%-76,5%=23,5%