gas hob gap beneath

Hi Guys, I've only recently found this forum and has to be said, there's some interesting reading still to be done but I have a question I can't find an answer to: I'm redesigning my kitchen and it's pretty small with restrictions for equipment location (doors on 3 of the 4 walls) and would...

Lots written about leaving gaps above, behind and to the side of gas hobs fitted into a kitchen worktop but I was surprised to see a recommended gap of 130mm beneath one of the gas hobs I'm thinking of buying (unless I'm misinterpreting these instructions)...