Chevy Cruze LT - adding additional mileage

Just bought a Trax from an easy to work with dealership, now trying to work a Cruze for my Mom, but she drives about 23k miles a year. Dealer sent me the lease program details for the Cruze, but I need nonstandard miles.

How/where do you find what the residual would be lowered by when adding miles?

Looking at a 24month lease with .65 residual or maybe 27 month lease with a base .63 residual, but not sure how to add miles above 15k/year. Would like to bump it to 20 or 25k.

Thanks in advance for any information.

Get her two for the [normal] price of one.

This is funnily the better option… Dealer says it is 20 cents a mile to add additional mileage. Will get a 36m 15k lease and hope to find another lease deal in 24 months and trade in early when she is out of those… keeping her current owned vehicle as a backup.