It’s incorrect to brand this as an across-the-board price increase. Some customers pay more, others pay less. According to Charlotte for the ‘large majority’ it’s a benefit.
It’s certainly not a price increase for fans of Essential. That’s down to 90p. 
& here’s a thought… although the new system is more expensive for heavy users of one product maybe it’s cheaper for a large enough majority of customers to actually mean less money overall for the company. ? It’s not impossible.