There seems to be some confusion regarding these two commands.
Although rarely used (one hopes) on the Expert Server, the are used occasionally to allow for departures or to, erm, gently remind pilots of their sequence. However, they are not equivalent commands.
This means exactly what is says. Don’t turn base as early as you would or if you look like you are about to turn base, maintain downwind heading.
Generally, it’s a good idea to try and determine why you were given this. We’re you turning base number 2 when your sequence is number 3? Are you a GA flying tight patterns with a departure queue growing?
You do not need to wait for a turn base command. You need to use your situational awareness to determine that on your own.
I’ll Call Your Base
This command should be self-explanatory, though somehow it’s not.
It means exactly what it says. Do not turn base until told “Turn Base”
Hopefully this clears up some confusion between the two commands.