House Hacking - Lender not considering rental income in basement?

[John S.]

Hey guys, fairly new real estate rookie here:

I'm house hacking and I ran into a bit of a crossroad, here's an explanation, I hope one of you gurus can assist me as I'm not sure what to do at this point. I want to use my rental income to offset my debts to buy my second property. Something called a "rent schedule" was done because I do not have tax returns showing my rents received, but it seems to not consider one portion of my rentals at all. 

First let me explain my situation, a bit long but I hope that's okay:

-Bought a 3 level townhouse in July 2020
-After a few months of remodeling, I rented the upper 2 levels in November 2020 while I lived in the basement of that same property
-I had to live in this property for 1 year because the loan was an owner occupied loan that required it
-I lived the entirety of 2020 and 2021 in the basement while I rented the upper 2 levels
-Just not long ago, I finally rent the lower level basement in April 2022
-I have tax returns showing the rents received from the upper 2 levels for 2020/2021
-My lender says if I want to have more purchasing power for my next property, we can use my rental income, but instead of just using my upper portion of the property,  (showing my tax returns for the upper levels (2021)) it turns out I could use BOTH the upper and the lower, which was great news, BUT a "rent schedule" needs to be done to INCLUDE the lower level. So what would be needed? A security deposit, a written lease, and first month's rent pertaining to the lower level.
- So, with this in mind, my mortgage lender estimates that my total rents received/rent schedule will be in a certain X amount of range
-Unfortunately, just about a week ago, when the rent schedule is ACTUALLY done, it turns out the rent scheduler appraises the ENTIRE rental for a much lower amount instead of considering the basement/house hacked portion of the property AT ALL, which I thought was egregious, all the rent scheduler did was pull MLS comps and make no distinction between the basement or the upper part. "There's nothing we can do at this point" - per my lender.
-Now I'm stuck with a much lower purchasing power because of this, my supplemental rental income coming in at something much lower than my lender and I had originally anticipated
-Some part of me is convinced that this rent schedule situation is not the correct way to go about this, I think it's unfair that if I make X amount of money on the entire property and I can prove it, it's still not being considered? This is more of a lender situation, but what do you make of this? In summary, I'm trying to buy another property, I already have a house that's making me X amount a month, but my lender, due to this "rent schedule" is only considering a much smaller fraction of the total amount so my purchasing power is much less than it "should" be. Lender said, "Once you have tax returns, we can use the full amount" but I don't want to wait another year as you can imagine.

Any help is appreciated, thanks!