Finer control of startup volume

Hello,

I would like to have finer control (higher resolution) of the startup volume on Volumio (running with Raspberry Pi and HiFiBerry AMP and DAC - 2 installations.) At the moment it can be set to 0, 10, 20, 30 . . . . I find that 50 is too soft and 60 is too loud. Single digit increments would be good - 0, 1,2,3,4, . . . .

Thanks

Boydwill