[Koha] Staff permission flag

Hello I just need a confirmation that whenever we assigned staff permission to someone in koha it generate some number depending on options permitted, for example full access flag id 1, only catalogue, 4, etc and for others number in 3/4 digits. My question is above numbers are fixed according to the options permitted and will it continue in next versions. Actually I am trying to develop some tool and authenticate on the basis of flag ID.