Crossing restrictions outside the US
In the US, while at cruise, we are usually instructed to begin our descent via one of 2 methods:
1. ABC123, descend FL240- whereby we start an immediate descent.
2. ABC123, cross XYZ at FL240- Here, it is (rightfully or wrongfully) interpreted to mean "at pilot's discretion, descend to cross XYZ at FL240". This is how pretty much all the Captains interpret it, and I've never had ATC ask why we are still level several minutes later.
My question is, if flying outside the US (Europe in particular) and ATC says "descend to cross XYZ at FL240", am I allowed to start descending when I please?
Thanks!