Is there a way to use MID function with an IFELSE condition

Summary:

We have an Account tree NOI_Cash NOI where all Levels above 0 have the "NOI_" prefix. I can use the MID function as a Custom Header but only works above Lev0. Is there a way to use IF or IFELSE in the function for the customer header so that IF Lev0 do not use the MID function? I've tried several approaches but cannot find the correct syntax is this option exists.

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25.05.72

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