Hello....yes I get around this another way, well 2 ways actually.

I wrote a wrapper for performance equations that works on a schedule (excludes data updates to perform equation). All you do is set it is run time (which is set after each run) and it works forward to the current time - so if you have 1 hours gap, set the run time to 1 hour ago. It is actually a bit more complex than that but you get the idea. What you need to consider though is why the PE did not run, if it is because the PI server was down then you probably don't have data for your inputs of your PE.

For another client we actually wrote a frontend for PI-ACE, well ACE was used as the scheduler. All PE were actually written as calculations using VBScript syntax and exposed "some" functions of PI-SDK to end users. This is actually a very good tool, in fact I believe OSI are already coming up with something similar with next releases of AF etc.

Now if you are feeling daring, you could write something yourself to do this using SDK or PI-AF :-)