I agree with Roff! Losing a minute a day means there is something wrong inside. If the watch is from the 1990's, and has not had regular service (or you don't know the service history), it is long overdue. I'm not sure what you mean by everything inside. Did they quote a new movement? If the current movement is beyond repair, then absolutely send it to BUSA. Your local watchmaker will not be able to get the movement from Breitling, and any other replacement (even though it works) will ruin the value of the watch.
I doubt that Breitling is trying to sell you parts you don't need. Since they warranty their service, they will replace worn parts that compromise the integrity of the case. It sounds like that is the reason for the crown and pushers.
Regular service will keep a watch running for a lifetime. I have a collection of railroad pocket watches that were mandated to be serviced at regular intervals. After 100 years, they still keep time to railroad standards.
Different railroads had different rules, but 30 seconds per week in 5 positions was pretty universal.