Regular depreciation for Short Term Rental properties

[Pandu Chimata]

Hello tax experts, I have specific question on filing taxes for Short term rental property (30 days or less). I am not talking about bonus depreciation here. 

My question - my CPA used to account for depreciation until last year as 27.5 years (residential property) but starting this year and going forward, he says it should be considered as commercial property depreciation rules (like 39 years) . 

Is this a  new change or he realized that he made a mistake in the previous returns? Any clarification on this appreciated.