Not entirely sure how this would be implemented to be honest, but the rough idea is a late stage reinforce upgrade, or more likely a galaxy perk, to adjust the amount of fuel is needed in a given day to purchase an unstable transit.
This would in essence allow the more proactive to spend their Transit points more frequently and gain the bonuses therein, as well as allowing the more lax to 'bank' more uses in total.
The most recent Multiplier within the recent galaxy was a step in the right direction for making Unstable transit feel as if it is keeping up with the other bonuses newer systems provide.
It is possible this idea is not the best way to implement an upgrade to Unstable Transit, and that more Galaxy Artifact multipliers are the way to go, long term. I'll admit, long term knock on effects and the math therein are not my strong suit.