Hi adonohoo,
You certainly made a great quality/value choice … and congratulations on your new mattress
The individual layers would be fairly similar in terms of firmness/softness but the most likely reason for your experience (both in terms of firmness and “bounce”) is that your Savvy Rest mattress had a Dunlop latex top layer and your Flexus mattress has a Talalay latex top layer. While the choice between different types and blends of latex is primarily a preference choice … there is more about how Dunlop latex compares to Talalay latex in post #7 here.
Phoenix