well, as west has suggested, should be easier or to round up, or to rewrite a good mapping by steps of 0.4%
but you will on video needs not be so happy from steps conversion I think. you will loose some definitions and you will have this kind of things:
''So exactly 50% doesn’t exist (127.5), it is either 127 or 128.
but peter444 seems to be in quite a need of precision on videos parameters.
a good other solution that takes a little time would be to remap but not with mapping functions, but doing like a grid or a dimmer law :
for each range of values, you will output the good value you need
aka: if incoming >0.14 and is < or equal to 0.18 you set your value to 0.18
this to be precise and have a customized table specific to your needs