Multi state investment properties, file taxes in resident state

[ThomasRoy Penland]

Hello, I have been involved with RE for a good while now but was contemplating having a Tax group help out with my taxes. I have done them myself for over 20 years and have properties in multiple states. I have always claimed the income on my personal return and only filed one state return (primary resident location).  The tax group said they would have to redo my taxes for each property in the properties state to get everything caught up. I don’t think this is necessarily the case. I wanted to know if anyone here has a similar set up and possibly would know wether I’ve been doing it all wrong for the last several years, or if the tax group might be mistaken?  Thanks in advance,  TR