Step A - Marginal Cash
Estimate the marginal cash per hour from each pass using the customer's spawn distribution and the pass's bonus mechanics.
Step B - Lifetime Gain
Convert that marginal cash per hour into lifetime gain over the player's expected N days of play.
Step C - Robux Conversion
Convert lifetime gain to Robux-equivalent at the in-game conversion (1 Robux = 100 cash [INFERRED-FROM-MECHANICS]).
Step D - R Ratio
Divide by the pass price to get the Robux-on-Robux ratio. R_ratio >= 1.5 with payback <= 14 days is the canonical Buy verdict.
Step E - Combined Stack
Toggle Paintbrush + VIP together to see the additive buyer path. If the combined Pass_1 + Pass_2 stack pushes the recommendation into Borderline, you have the highest-expected-value purchase order.