Shocking co-payment amount

I am on Momentum Ingwe option. I filled a script today at Dischem after seeing my network GP. There were 7 items on the script, 2 of which were not on the formulary and which I paid out of pocket. <br> <br> Then the bill shock came. The total of the remaining 5 items (all prescribed from the Ingwe formulary) was R254.43 of which Momentum paid only R162.12. So by doing the math the co-payment for the formulary related items was R92.31, which is almost 60% of the original amount for the Ingwe formulary prescribed items.<br> <br> How on earth is it possible that using an Ingwe network GP who prescribed medication from the Ingwe formulary and filling the script at the pharmacy of your instruction (Dischem), still results in such a huge co-payment? What then is the point of having a formulary and designated pharamacies at all? What must a person then do more to avoid co-payments, as I had done everything you asked (Network GP, Ingwe formulary, used Clicks or Dischem as per your instructions).