Single Family Comparable Rent Schedule - check your software, instructions are pre-printed. Determine a credible opinion of market rent for a single family residential property either currently, or potentially, a rented dwelling versus owner-occupied. Strongly recommend referring to the USPAP Competency Rule and taking a couple of courses on the topic.
I just taught an 8-hour Cost Approach course offering this last weekend. The course includes a case study wherein the participants fill one of these out. For someone who's never done it before it can be an eye-opening exercise. For most people doing it for the first time, it takes between 45-60 minutes to make your way through it all, and that's IF you have a current cost reference.
As for why a lender would want it, they might be trying to see if you can back up the costs you used in a cost approach, or they might be trying to get an insurable value.
If it's the latter, you might try inquiring to see if perhaps they'll take a cost breakdown from Building-Cost.net instead. If so, that's a 10-minute process at the most. The best part is that it's free.
There are two 1007 forms. Fannie Mae's 1007 is the rental comp schedule and is likely the form the lender is looking for. The other is the Marshall & Swift 1007 form, which I doubt the lender even knows by form number, and quite possibly doesn't know the form if it were in front of them.
Every appraiser should know how to fill out a Marshall & Swift 1007 Cost Form before they are issued a license. It is not required, but it should be. If you do narrative reports, field reviews or comprehensive cost approach analysis for clients, it is essential for you to know how to use this form. The cost section on a URAR is a joke and many appraiser make it a bigger joke.
I bet you are being asked for a rent schedule, though.
If you are being asked to do the 1007 sq ft cost form, you can go to Swiftestimator.com and for a small fee complete the cost approach and get it printed on the 1007 form. I use this on each appraisal I do that requires the cost approach.