Assuming you really mean to say add extra metal clips or ties or loops of builders band between the original plastic supports, without removing the old ones, yes that is fine, and indeed seems to be the most common 'upgrade' approach. Spacing can often be a bit wider than normal as the aim is not to keep it  tight to the ceiling or wall but to just stop it all dangling down in potential snag loops. Arguably in places where if it did drop it would be stopped by something else that is not going to fall - pipes or ceiling supports perhaps, then additional supports can be omitted altogether. More commonly it will be a judgement depending on the ceiling height and how much droop is acceptable and still well above head height and not so far apart as to be or in the eyes of any inspector, look, utterly ineffective,

Mike

Consider not just the clips/saddles/band but how they attach to the structure - screws into plastic wall plugs might be OK in a wall where gravity is acting at 90 degrees to the hole (i.e. the screw wouldn't fall out even if the plug was missing), but hanging down from a ceiling is a bit more challenging. For nail in fixings consider than if you have fewer than normal then each clip will have to support a much greater weight of cable when the plastic ones fail.

   - Andy.

Thanks for input on this, much as expected, but grateful for the confirmation. Your advice is much appreciated.