Anchoring Pool Liner Extrusion - Wood vs Concrete ?

Hello Everyone,

I'm having some masonry repair work done on my IGP walls to support a new liner extrusion. The mason is recommending that he build the wall up an 1.5" higher and avoiding using the PT wood to support the liner extrusion. The pool contractor doing the liner is fine with this. My question - is this actually a better option ? It sounds better, but screwing into concrete is more complicated than screwing into wood. I'm concerned about sections not being anchored securely - should I be ?

I would be interested in hearing people's thoughts on this. Appreciate any help .

IGP | T-Shaped 18x36 Deep | 12x18 Shallow | 43k Gallons of Water

Thank you !