At first glance, there appears little physical difference between 1:300 and 1:285 models of the same original object. Placing them side by side however, reveals a significant size variation that belies the 5% mathematical difference.
This can be put to good use by wargamers – using the larger 1:285 scale models for “heavy” units, and the smaller 1:300 (6mm) scale models for “regulars” and lighter units. Where it is not appropriate to mix the scales is when, for example, creating vehicle units of identical vehicles such as a tank company.
In such cases, it is also not recommended to mix model manufacturers, even if they are of the same scale, the subtle design differences will become glaringly obvious (even at this scale) and make the vehicles look like different marques, not just variants.
In scale modelling, these “micro scales” are rarely used other than for larger individual vessels such as coastal shipping and factual spacecraft. There is no equivalent in railway modelling, and therefore the scales are mainly the realm of wargamers and military colleges.
(page incomplete – more to be added)