Update Expressions via Macro Input

[AGilbert]

Is a batch macro the only type which allows for expressions to be updated from input anchors? I was surprised to find that a standard macro errors as below.

Mocked examples for each macro type are attached. Both the standard and iterative seem to be replacing the '50' in the expression '[value] + 50' with null resulting in an expression which ends with an operator (i.e. '[value] +').

For context, I was working on weekly challenge 66 and used the control input to update a mod function within the formula tool's expression editor. I designed my solution this way to separate the app interface from the macro. My submission is  Re: Challenge #66: My Wine Problem - Page 26 - Alteryx Community

Thanks!

Alex

[AGilbert]

Sorry for the duplicate message. The snip seems to have not attached. 

[antonio61323]

bump