Link 3 non adjacent cells with formulas, avoiding circular reference

[Evylrat]

Problem, I have 3 cells that are all related to each other; a level of wall top, level of wall bottom and height of wall. All three are linked via formulas


A3 (top of wall) would have formula A4+A5 (bottom of wall + wall height)
A4 (bottom of wall) would have formula A3-A5 (top of wall - wall height)
A5 (wall height) would have formula A3-A4 (top of wall - bottom of wall)

Example
3 5.775 Top of Wall (above Datum)
4 5.285 Bottom of Wall (above Datum)
5 0.490 Height of Wall

If I enter 0.49 in A5, and 5.285 in A4, then I'd like A3 to be calculated automatically.

If I change A3 to 5.875 then I'd like A4 to be calculated automatically and the accenting change to indicate to the user that A4 has been calculated.

3 5.875 Top of Wall (above Datum)
4 5.285 Bottom of Wall (above Datum)
5 0.590 Height of Wall

So from the accenting, in the top example I can see that I manually entered the top of wall level, and the height and bottom level were calculated.
When I entered a new wall height, I can see that the top of wall was calculated.

For reviewing purposed, and because this would be part of a calculation sheet, I want to keep formulas out of macros if possible so that the user (with NO VBA experience) can easily see how cells values where calculated, which is why I was trying out CellEntry() which I found on this forum (GREAT script btw).

I was thinking that a macro could wipe the last entered value, so CellEntry() would return that cell back to it's original formula maybe

If there is a non macro/VBA alternative that would be even better.