I have several day care clients. I understand how the time-space percentage works. 

Normally, we figure the time-space percentage through square feet, figuring space that is exclusive to the daycare, space that is jointly used, and then multiplying it by the hours of operation percentage. That all makes sense.

And in all of my clients, I've just used that same percentage for all of their home office expenses -- taxes, interest, depreciation, furniture and fixtures, utilities, insurance, repairs, etc.

Well, I have a client who has been assigning a different percentage to everything. Their "time-space" percentage is just shy of 24%. And I completed their return using that #. But then he came back and said, Oh, no, the landscaping is 100% for the daycare, because we wouldn't do it if we didn't run a daycare. And the office windows are 50%, not 25%, because we use that office 50% for the business. And the bathroom remodel is 100%, because that's the downstairs bathroom, and it's only used for the daycare. And the utilities should be figured at 50%, because about 50% of the utilities are used in the daycare.

Now, I will buy 100% for the bathroom remodel. If the downstairs bathroom is 100% for the business (they hadn't told me that when I started, which they should have, but okay), yes, they can depreciate that 100% as business. And I can accept a 50% for the office, if they have written documentation to support that they use the office 50% or more for the business. 

But the utilities? The landscaper? Has anyone here ever heard of anything that allows a higher % be used for utilities or maintenance than the time-use %?

And most importantly, if I'm right in saying this is wrong, can anyone here please help me find something that will show this client that it's not allowed?

TIA