Combine discounts

-- HikaShop version -- : 3.4.1
-- Joomla version -- : 3.10
-- PHP version -- : 7

Hi Team,

It looks like it's not possible to combine discounts.
For example we want to give everybody € 15% discount until the end of the year.
But we like to give our access level (shareholders) a flat amount discount from € 10,-

But when we check this on the website it's only use the flat amount and not both.
When we depublished the flat amount Hikashop use the percentage, so both discount's are working fine but not when we published both.

Is this a normal behavior because it is otherwise difficult to display?

Kind regards,
Lumiga