Ann: Q3 trading update - Ongoing SaaS growth, page-3

Agreed, good numbers and a red hot long term business.
My take is they are pitching enhanced capability and cost predictability of the saas option to their existing customers, so those customers moving over initially are flat or maybe a slightly lower revenue compared to py as you go transactions, so we aren't seeing all the growth coming straight through in total revenue.

but once they are using the app, and using extra features customers won't be able to go back to the more limited per transaction model, so can accommodate price rises, dramatically growing margin in future years.