both cadre start with grade 17 DMG got house,vehicle,gurds,staff on 1st day of its office duty because its requirement of their duty in far flung areas like badeen,kachi,rajanpur etc etc because they need to work in fild rather secteriate in most cases,further more if u opt for secteriate u wont get car and house

on the other hand in IRS u will get all above mentioned perks slowly slowly woth progress of your grade because probationers are posted in capital cities not far flung araes



i hope u got my points and im a MISS not a BHAI