What type of entity is this? A Partnership (Form 1065)? I am going to assume this is NOT a corporate return you are doing.
Just because the program gives you an error about the placed in service date, does NOT mean you should lie and use a different date. That different date is what is throwing things off.
If you use the proper "placed in service" date, it should do everything correctly.
As for the error message, that is a program limitation. You can either (a) ignore the error and file by mail, or (b) use the fake 10/10/15 date and leave the "prior depreciation" BLANK. However, whenever you sell the property (or in the final year of depreciation) you will need to MANUALLY make some adjustments for the 7 months from 3/20/15 and 10/10/15
