I would have to ask, what is your default unit of measurement?

The bump strength is measured in such.  I use the cm, so when applying bump map, the strength of 0.05 is that in centimeters.  If you use feet, then 0.05 is feet equaling 1.5 cm or 0.6 inches.

Once you set strength, then when you change the default unit it will track it, changing to the equivalent.

Maybe you can show screen shot of material room settings so better judgement can be made.