Inconsitencies in function declaration in Report class (breaking LYBUNT & SYBUNT date options)

Am noticing that there are 5 functions in the CRM_Core_Form_Report class which are static while rest are over-ridable. There is no obvious reason for these functions to be different & one of the great things about the report class is it's use of OOP.

Suggest that at some stage we convert them to being non-static like the rest (I noticed when trying to over-ride getOperationPair but will use a different approach)