Wound Vac problems

I had a panniculectomy on September 29th of 2017. My surgeon opted to put wound vacs on me to promote faster healing, when I started my wounds (2 of them) were 6cm wide and 9 deep. The wound care nurses decided to put black foam and drape from hip to hip in order to heal my incision site faster which 80% of it has closed up completely. It has now been 5 weeks since my surgery and my wounds are 4cm wide by 7.5cm deep. I have been told they are not healing as rapidly as they thought they would and I now have An extended healing time to 7-8 weeks instead. My question is with having only healed 1.5cm in depth in 5 weeks is an extra 2 weeks really going to heal me 7.5cm? I have struggled with constant drape leaks some of which are as long as an index finger or two (I've patched 3 holes just this morning), could this be a reason as to why I haven't healed properly? My in home nurses give me vague answers and don't seem to know.