• CS Agents utilize the "Book Appointment" button on Opps to auto-generate available appointment times for Sales Reps in the field
• The need is to have the first appointment be at the start of the day, and the next appointment generate after the first appointment ends plus drive time to the next appointment
• Goal is to avoid set appointment start times and have appointment availability be based on drive time between appointments with a goal of having as many appointments as possible scheduled in a day
• EX: Appt #1 starts at 9am and is an hour long ending at 10am, the next appointment to populate as available should be 10am + drive time to the next customer's home, so if it is a 15 min drive the appointment would show to the CS Agent as 10:15 am...and so on and so forth

Any idea why I get a "field integrity exception" error when I try to update SOME PricebookEntry objects?  It doesn't happen for all Pricebooks/PricebookEntry objects, just some, but I can't figure out whether there's a pattern.  I'm definitely using a valid PricebookEntryId.  Any ideas are appreciated.