BPM to prevent order creation if quote config version is not current

Hi every one,
We have around twenty fairly complex configurators which often require minor updates and as such, I do not create a new revision. We also have many quotes which sit in our system for weeks sometimes months. What I want to do is to create a BPM which prevents any lines on these quotes from being converted if the version number of the configurator used does not match the currently approved version.
We use smartstring for part numbers so the Verify Existing Configurations does not help us, it errors every time I run it.
I just wondered if anyone has done similar and can give me some pointers. I am assuming I would be looking at a pre-processing method directive and using the PcValueHead, PcStatus and QuoteDtl tables but I am unsure on how.
Thanks in advance,
Adrian.

You can link QuoteDtl -> PCInValue (Sub Query because it has more records per line), - > PCStatus