I think this is perfectly fine. You might not have any point (on the map) where the output Raster mean value is equal to 5.
Another way to check using Raster Calculator.
Let me consider there 3 input raster layers, viz., ras1, ras2 and ras3 with influence factor 24%, 55% and 21% respectively.
Expression
("ras1"*0.24)+("ras2"*0.55)+("ras3"*0.21)
What is the maximum value of the above output raster?
Think Location