What is the process for entering data during an interim year when only several months of financial data is available?

Just enter the ACTUAL 2018 balance sheet figures.

For the income statement, they are dated 7-25-18. This is almost 7 full months, so you could either adjust 7 months to 12 months or adjust say 29 weeks to 52 weeks or adjust 206 days to 365 days.

I would just adjust 7 to 12.

For revenues, pretax income, owner compensation, non-cash charges (which are $0) and interest expense through the end of July, just divide each figure by 7 and then multiply by 12.

You may have to estimate owner comp because it is not broken out on the income statement. They have donations/health ins/life ins/entertainment and meals for owner perks, but no salary is broken out.

The other caveat is if it is a seasonal business. Looks like a construction firm - if in the northeast, slower in winter months but roughly half is at beginning and half at end of year so no adjustment may be necessary.