Frag tank: Grow out on tiles vs plugs

[cflow]

I have a 30 gallon frag system that has mainly plugs until i get my bigger system built and stable. I usually just mount my frags on the rock work in the best way for the coral to grow as they should, but in this frag tank I'm limited to just plugs. I noticed that the corals that would normally heavily encrust aren't growing as rapidly as they normally would . My theory is that because they only have a small frag plug to grab hold of, they aren't taking off like they would if they could lay down a big base. For example, my red planet frag has encrusted down the frag plug but hasn't put on any vertical growth. Has anyone noticed a difference of using frag tiles vs plugs for better growth if they're not mounting it on rock work?