Depends on:
1. Aircraft you did your FAA CPL MEIR on
2. Where you live
3. Checklists used by the schools.
If there is a school nearby that uses the same aircraft, with nearly the same checklist, the decision is made for you.
Before you start your conversion, make sure you are familiar with the differences between flying IFR in uncontrolled airspace (Class F and G) and flying IFR in controlled airspace. This is something that is taken for granted, generally, in the USA. There is a big difference here in the UK.