@BButz - When you think about it, there is a pretty large overhead in the initialization and execution of a workflow. As I understand it, each thread like this is effectively a AWS Lambda environment (or something real similar), and competes with other threads of execution for resources.
Nothing in HubSpot is really guaranteed as real-time, so you have to expect a spectrum of delay times for all functions. You can potentially optimize things to be as lightweight as possible, and the action is reliablly executed, but I always assume that timing between functions is a bit indeterminate.
Hope this is helpful.
Steve