I'm not sure if clever or sneaky is the right word but all DAZN are doing with this price increase/changes is making the Joshua fight PPV without it being PPV. They know there's lots of casual fans that want to watch Joshua but who aren't going to sign up for a year to DAZN so this pricing structure means that those fans are paying the typical £20 PPV price to watch Joshua and the tiny number of hardcore fans will be pushed into committing to a 1 year contract rather than not being tied in.
The whole sales pitch about DAZN making boxing cheaper for fans was always a load of bull**** to all but a handful of people but it's now at the stage where it's hugely more expensive for the majority. Pre DAZN the majority were watching boxing essentially for free - they were paying their Sky sub primarily for the football and boxing was a bonus and if they wanted, they could pay £20-25 a few times per year for the PPV events. Now it's been fragmented and you're having to pay either an extra £100 up front or £20 per month to watch broadly the same content. Lets just hope DAZN don't end up with 10-20 PL games in the next rights sale or else that £20 per month will probably become £30.