The MicroChip assembler MPASM accepts various styles, over the years different manufacturers have all used different styles - including the formats for numbers in different bases. MicroChip rather cleverly added support for various of these, so people moving from other processors found it easier.
So it's not really a question of 'MicroChip style', but more of 'Motorola style' or 'Intel style'. Personally I came from a 6502 background, and that was more like Motorola than anything else.