I'm afraid this will not work; there can only be one discount code per offer. A discount code can only perform one function at a time, the same code cannot perform two separate functions. There is more information here on how discount codes work & the different types of codes you can create. There is no workaround for this in the admin section apart from creating two separate codes, but this app called Discounts Combined may be of use to you! The Bold Discount app is also quite versatile so this may also help you out.
Would it be possible for you to create two separate codes? Just to gather more context, can I ask why you want one code for two discounts?
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