This is a strange way to use the status_dict dictionary: it has speeds as keys, but also 'subs' and 'available_speed'.  These last two keys are overwritten in the case that there is more than one speed with available transcripts.  Later, you loop over the items in status_dict, but don't account for the fact that two of the items aren't speeds.  The logic works because the values of these two keys are not falsy.

It looks to me like you'd be better off with a list of the speeds that are missing, and simple variables for subs and available_speed.  The dict is just a complicated way to get those things.