Funny that the engineers do direct starts all the time and the US pilots that transferred to Australia, and the Swedes did direct starts, hey, but what would I know.
Oops what start method is that???
If during a ”Motoring” start the IGN switch is set to NORM and the CL is advanced to START at about the same time with the IGN switch leading the CL movement, the start signal to the start relay will be interrupted momentatily similar to a poor ground power unit.
The issue with PDU frying is when selecting fuel and IGN too close together, especially IGN immediately prior to fuel, this has nothing to do with motoring vs direct, its only an issue during motoring starts. It is mainly because it is designed for direct starts, but a motoring start is preferred in any turbine to increase airflow prior to combustion. The start sequence requires both fuel in start and IGN auto to engage properly, if you switch it all on during motoring at the same time the system takes a second or two to recognise where its at and continue, a bit like mashing the keyboard on an old computer. Watching some of the euro operators new procedures actually seems to go against this advice and has the FO putting in fuel at the same time as the captain selecting IGN, seems way overly complicated and runs against the advice leveled. At least the Aussie procedure has the Captain doing all the start so its a clear order.
PS apart from PDU issues of spiking power from an abridged stuffed up motoring start the other downside to motoring are increased wear on everything else not the hot section, starter motor, battery, even just the increased time at load across the electrical system, longer load on the GPU if used, etc etc... Direct starts is designed to get the engine up and running as efficiently as possible, not necessarily the absolute best heat wise across the hot section.