Hi Norman
To make sure your decking is warranted by the manufacturer you have to follow the instructions.
Whilst it may seem plausible to fasten at the ends for ease of board removal it would not be advisable. It won’t be covered by the warranty and the boards will move. This is for ALL decking boards and by any manufacturer including softwood, hardwood and modified wood.
Maybe best to design a few inspection hatches for maintenance, this would be normal in this instance.
Hope this helps