We have similar story. Nicholas is now 8 and we and he feel he doesn't need another treatment. His doctor said he could use one more, but up to us of course. At age 6 you are well outside of the growth phase and involution likely will be slow if any...but it shouldn't matter if you do it now or wait now.
VBF Director of Family Services
vbfadvocate @ live. com (no spaces)