If AND OR formula help

Hello,
I am looking for help with a formula to measure on time shipments. Variables would be:
A1 = Date of Order
B1 = Customer request Ship date
C1 = Actual Ship date
D1 = 10. This is the maximum number of days from Order to Ship that is committed to for all Orders unless Customer requests a longer Ship date.

Challenge is how to measure the different scenarios. Examples:
1) Order on June 1, Customer request date June 10, Ship date June 10. Perfect! Result of 0 (zero).
2) Order on June 1, Customer request date June 8, Ship date June 10. Perfect! Result of 0 (zero).
3) Order on June 1, Customer request date June 8, Ship date June 9. Perfect! Result of 1 (one).
4) Order on June 1, Customer request date June 10, Ship date of June 11. No good. Result of -1.
5) Order on June 1, Customer request date June 15, Ship date of June 15. Perfect!. Result of 0.
Challenge is how to switch up the calculations when the customer request date is longer than the 10 day agreement.

Any help would be appreciated.

Try

=MAX(B1,A1+D1-1)-C1

I tried to interpret your request and came up with this

Thanks to both of you for your help. Root, after removing the -1 from your formula it worked perfect. Thanks again!

Originally Posted by sfitzpat

... Root, after removing the -1 from your formula it worked perfect...

Could you please post an example?