If the demand for this offer is so intense their servers melt down for hours on end it seems this is pointing to a huge opportunity the rest of the year to reach all those who think 4x the current sales price (whether for the full version or the update) is "unreasonable".
One data point would be myself: as a single developer, spending 100€ on AppCode never felt "reasonable" considering XCode was free. 25€ is an instabuy of course - so it seems to me the "sweet spot" is more around 50-60€ where they'd reach far more than twice as many customers than at 100€...