I suggest that CMDR receive commodity requirement discount in their future colonized systems based on how much their previous systems are developed. For example You can use very simple formula
Discount = Q * TotalTierPointsUsed / NumberOfColonizedSystems
This gives average development of systems CMDR colonized
Discount = Q * TotalTierPointsUsed / NumberOfColonizedSystems
This gives average development of systems CMDR colonized