Pensioners discount muddle

At my local Pick n Pay I get a pensioners discount of 5% & I shop Mon to Thr to take advantage of this. With specials, the normal price is charged & a reduced discount is app****. eg. a R40 item on special for R30 rings up as R40 with a reduced discount of, say, R5. So I've been charged R35 for an item marked R30. It was explained that the discount is recalculated because P&P can;t give discount on top of specials. So pensioners are now disadvantaged right? Well not really, if P&P gave 5% discount on all items except those on special (quite reasonable) it works out almost the same & people would not see an item on special, reflecting as more expensive than advertised. I have an issue being charged R35 for an item advertised as R30,