Yes % Zn equiv is caclulted additavely for each element...

Yes % Zn equiv is caclulted additavely for each element converted to Zn% at the specified price (prices written as a foot note). Importantly (I believe) it assumes 100% recovery of each. That is patently not the case in reality.
Copper recovery was a problem previously but is assumed to be improved with fine grinding.
Gold recovery is poor at 20% and silver 50%.

Note: There are numerous nuances for new material assumed to be ore but whose mineabilty and metallurgical response have not been tested. These are left to the process of converting resources to reserves.

In the absence of a broker (model) report that does just that. If one wants to seriously assess the effects of finding extra new ore unfortunatley one needs to construct the model for the DFS and plug in things like different currency, metal prices and ore tonnages. Being a ploymetallic or body including three type of tailings and UG ore it requires quite a bit of work. I found Redbeard's rough method using current metal prices and currency sufficiently accurate and came to the same conclusions as he did.

Look the DFS highlights some very positive aspects like. High IRR and excellent operating cost after deducting (non- Zn) by product metal credits. However, the result is gutted by the issuing of too many shares and too low a gearing rate. That's what gets me to Redbeard's conclusion.

One saving grace method would be a very aggressve share buy-back from cash flow generated by getting to G2 very early but how likley is that if the PE holders hold there reigns. Like a bank they will want to secure their capial outlaid. There's even little scope for benefit form re-financing at a lower rate soon after the UG mining settles since there not that much debt.