Modeling Cash Flow Statement from 10-k

I've read elsewhere on the forum, that it's often a waste of time trying to tie out the historical financial statements of most publicly traded companies. However I want to make sure I'm not leaving any important line items out in my projections.

For example, I'm looking at a REIT (SNR) that only has one line item on the income statement for Depreciation and Amortization. However, on the CFS there are the following line items: Depreciation of Tangible Assets, Amortization of Deferred Financing Costs, Amortization of Deferred Revenue, Amortization of Premium on Mortgage Notes Payable. I'm assuming all of these are captured by the D&A line item on the IS, even though they do not tie out. So I deleted those line items on the CFS, and just forecast one single D&A line item on the CFS by linking the D&A from my IS projections.

Is it appropriate to simplify things like this? Or should you be keeping every single line item that is listed on the CFS in the 10-k?

Appreciate any help on this. I've worked through breaking into wall street's modeling courses several times, but an actual 10-k isn't quite as neat as those case studies