I seem to have resolved the problem, in Revit. I have attached the project files here with the fix. In this screenshot, you will see I have achieved the desired equalities:
As an aside, please do tell me the correct way to do equalities on floats, if not through text panels. Do I just eliminate the panel and send the data directly to the Equality component?
It seems the problem was in fact the result of destructive (i.e. permanent) rounding done by Revit on the input elevation numbers. This permanent rounding is a function of the Project Units. I have documented my testing of this problem at this Revit Architecture Forum post (Solved: Project Elevation in Decimal Feet - Survey Base Point - Autodesk Community).
At the suggestion of @SteveKStafford, in his response to my thread, I explored a solution: setting project units to Feet (decimal feet) with the necessary number of decimal places in the rounding, prior to inputting the Survey Point and Base Point elevations in decimal feet. Then, it is possible to switch back to Feet and Inches (fractional). This causes the elevation reported by the Properties Panel for the Survey Point to be rounded into fractional inches, but it seems that this rounding is non-destructive (temporary) and can be reversed by returning the Project Units to Feet (decimal feet). Actually, even if I leave the Project Units as Feet and Inches, the Project Location Rhino.Inside module is reporting the correct decimal feet elevation for the Survey and Project Base Points.
So, it seems that if the Elevation parameter inputs of the Revit Survey Point and Project Base Point do not match the Project Units, including the Rounding Increment, then that input is permanently (destructively) rounded up or down to match the structure of the Project Units. However, after the input has been made, changing the Project Units, and changing the Rounding Increment of the Project Units, does not seem to destructively modify the Elevation parameter value of the Revit Survey Point and Project Base Point. It seems possible to change Project Units and Rounding Increment back and forth with no effect on the values, as documented in my Revit Architecture Forum post, linked above.
The one piece I am unsure about now is why if I change the Project Units to Feet and Inches after inputting the elevation parameter, the Project Location Rhino.Inside grasshopper module is reporting in decimal feet. This suggests that the Feet and Inches Project Unit schema is more superficial than the Feet Project Unit schema. Something to test further.