ann out: op exept gravity gold recovery, page-54

"Well i would seriously be looking for a good second hand ball mill or placing one on order as an extra 11% of what could well end up several million oz of high grade free millin ore is well worth the extra capex"

Trtkjd1, its not just the capex savings of the 88% recovery plant, its also the fact that it is able to run with much lower energy requirements and that too is a big advantage.
Also the 88.4% result is not considered final;
"Gekko work considered interim as further flotation work and processing / tail reconciliation is underway"
It would be excellent to see this very low cost option reach 90% recovery. Even if it does though, the 97% recovery option may still prove better.

Either option is excellent without further improvement, and they will work out what is optimal.