For each pleat they took out, they would have needed to take one full sett of material from the inverted pleat to add that pleat back in. Taking out 2 pleats and adding them back in at the inverted pleat would have required two setts. It looks the size of the sett is around 7". There might have been 1 extra sett in the inverted pleat (i.e., an extra 7"), but there couldn't possibly have been an extra 14" in the inverted pleat in the original kilt. So it remains a bit of a mystery!!

But! What matters is that you like the job they did, and they clearly did a fine job!