Cost savings of doing a loft and ground floor extension at the same time

[MusicMum80s]

I'm buying a house that we ultimately plan to extend through both a loft conversion and a ground floor extension. I am trying to see if its worth doing it all at the same time or the stage the work. I've read that its cheaper to do both at the same time (I guess only one set of site set-up costs etc). If anyone has received quotes to make this decision, it would be great to get a sense of the potential savings so we can run the financial analysis.

TIA

My experience is that it's more expensive to bundle jobs together as builders are able to disguise more profit into larger quotes. I get as little as possible done by one builder at a time. The prices seem to get less inflated that way.

There really aren't any significant savings involved.