is it not the case that cross crediting is valid only for the revalidation of an IR?
Whopity has provided a reference to the relevant amendment. Appendix 8 to Part-FCL was amended by Commission Implementing Regulation (EU) 2019/1747 in October 2019 to include renewal when cross-crediting of the IR part of a class or type rating proficiency check. This is embedded within the latest version of the Easy Access Rules to Part-FCL dated August 2020; see page 1241.
ifitaint...