Inserting MiscCode by BPM, Can I set the percentage field from the MiscChrg table instead of a static value?

I have a BPM to add a misc code line for every line that meets a specific criteria. I’m using the “set field” options to set the value of the misccode, description, freqcode, type, percentage, amount, and docamount fields. Is there any way I can pull the percentage amount from the misc charge table and populate the percentage field in the set field setter instead of making it a static number and having to change it in both places when it does change? Any help is greatly appreciated!! Thanks!