The ideal situation would be for that entire block to have a cooperative parking arrangement. I know that the owner of that strip mall, and the adjacent Uptown Theater complex to the south, Larry Sells, has proposed adding a 4-story apartment building on the parcel west of the current retail buildings--facing Pennsylvania (indicated in red on the photo). I don't know if those new units will require spaces on the roof of that garage. Sells might put the parking underneath on the current surface lot. I guess it depends on how many units would be in the new 4-story building.
That strip mall roof garage has at least 145 spaces. The Ambassador Apartments have 116 units. There is probably room for additional parking for the Knickerbocker Apartments on the roof of that garage-in addition to the small surface lot to the east of the Knickerbocker building. That surface lot and the four garage spaces in that small building on that lot could house about 25 cars alone--without the spaces on top of the retail building. The Knickerbocker looks like it has 24 units, so it might not need any parking on top of the retail building at all.
Perhaps Larry Sells could redevelop the Knickerbocker Apartments at the same time they are building the proposed apartment building along Pennsylvania. They are on the National Register of Historic Places, so historic tax credits would be available for the renovation.