RTL_RETURN_ALT is it available in ArduCopter?

I’d like my copter to RTL at certain altitude. Is there a command for that?
When I set RTL_ALT, it only works one way: if the copter is below, it will climb to RTL_ALT and return to land. If it is higher than RTL_ALT it returns at current altitude without descending to RTL_ALT first.
I believe in PX4 this command is RTL_RETURN_ALT but I’m not finding it in AC.
Or perhaps there is another way to do that?

RTL works as you described: it will maintain current altitude if above RTL_ALT. This was done for safety reasons as it minimises the risk of hitting something during RTL (in most cases).
Depending on your mission profile, Smart RTL might be an option for you to look at (https://ardupilot.org/copter/docs/smartrtl-mode.html), which will RTL via a simplification of the already flown path.

Thank you James. Saves me time for searching for a command that does not exist.
It feels to me the software is going same direction most governments do: they try to protect us from ourselves. No sugar in your drinks - not safe for you.
Jokes aside, this should be a default setting, but I should also be able to set the return altitude if I need to. And I do need to. Especially during development of my copter. Now I have to find a go around and most likely will end up with a less safe approach.

A similar thing happened to me before. One feature has been eliminated in newer versions. Also for “safety” reasons. It was so crucial for me that I am stuck with an old version of the firmware. A body of mine is trying to change the code to enable this feature in the new firmware but I’m afraid that this will wreck my precious prototypes before he masters his code.

Thanks again for your reply.

Please raise this in the GitHub issues list: https://github.com/ArduPilot/ardupilot/issues. That way it’s recorded, and might get some activity. Personally I agree it makes sense to have a flag/param to choose the behaviour. Alternatively, a lua script could be an option for you.