Error when using replacement path variable in exception range

Question

I'm trying produce a check report that produces exception highlighting based on a range determined by the associated characteristic.
eg.
For Check 1, highlight cells in red where the associated key figure is between 1 and 999.
For Check 2, highlight cells in amber where the associated key figure is between -999 and -1.
Now, I know that the lower and upper limit of an exception can be populated by a formula variable. However, when I create a formula variable that uses a replacement path to fetch the limit values from the associated Check and use that in the exception, the query errors when I try to run it:
System Error: 'Variable name ( technical name ) does not exist or is incorrectly used 4 New Exception.'
The error long text suggests that the variable is being used incorrectly, even though it says for Formula variables:
... can be used in all cases. Note: Formula variables can have units or be without them. Incorrect use can also arise here since the system always calculates in accordance with the units. Formula variables can also be used to create the upper and lower limits in exceptions.
In this case, the formula variable does not have units.
Interestingly, but equally unhelpfully, if a regular constant is used instead of a formula variable for the lower limit, but a formula variable is still used for the upper limit, the error message changes to:
System error in program SAPLRRI2 and form FAC_VAR_IN_VREP_INSERT-1-
The query works if the formula variable simply holds a default value, so the problem clearly appears to be with replacement path. If BEx doesn't support replacement path formula variables in exceptions, then aside from the fact that it would be useful if that was stated in the errors, what alternatives, if any, deliver the functionality of exception ranges that change depending on the corresponding characteristic.

Answer 1

I put in the curly brackets so my formula now reads
"Total inquiries for " + {CnAttrCat_1.CnAttrCat_1_Description} + ": " + ToText({@InquiryTypeSubtotal})
Now when I check the formula I get the error message "This field name is not known."
Alec