Hi,
ok, the behaviour you are experiencing is actually by design.
only ever one discount – the best/highest one applicable (may that be from the discounts or the codes) – will be applied.
otherwise you might end up with a sum of discounts that’s higher than what is actually in the cart as in theory you could have 50 discounts all giving 10% off so you end up with 500% off
(though obviously one would progrmatically not ever apply more than the sum of items)
in any event, i will think about adding a checkbox perhaps in the coupon codes to allow accumulative/multiple simple discounts as well
needs a bit of thinking about