Might be indeed a company procedure as we use boeing provided company tailored manuals. However, as clunkdriver so aptly remarked it is simply airmanship to check every couple thousand feet on cabin rate of climb, cabin altitude and most probably temperature as well. Any non-standard configuration for performance purposes (bleeds off take off) has to be reconfigured to standard setup at 5000ft latest, preferably around 2500 as soon as flaps are up. the FL100 check is only a last line of defense check as even a completely unpressurized aircraft won't have have 10.000ft cabin altitude by then and you still can reconfigure or level out at FL100.
Anyway, the helios case is covered very early on the ground and thereafter any reconfiguration of the pressurization system has to be done according to specific procedures, while airmanship dictates that cabin pressurisation is checked every couple thousand feet anyway with a mandatory standard setup latest at 5000ft. Stupidity and bad training cannot be covered by checklists.