Hmm. That's not my experience from, for example, Agrarian Skies or the Direwolf20 packs. I almost always use sprinklers to 'buff' my farms, and this is the first time I've had it bonemeal grass to get flowers. Adding bonemeal to the sprinkler is supposed to add even more growth to the crops you plant, but I've never seen that spawn flowers either. Personally, I don't use bonemeal in my sprinklers because I've never found a good way to automate it...
I think it might of been effected on Agrarian Skies because of the tweaks made to the things that can be spawn when using bonemeal. I think its more effective in this pack because of the pneumaticraft plants. I could be wrong I'm the same with not using bonemeal in it, and really didn't see a huge impact with using it.