HTC One M8 3G only for PagePlus Pay-as-you-go

[AC Question]

PagePlusCellular pay-as-you-go plans available for 3G only

according to: devicehelp.optus.com.au/web/htc-one-m8/calls-and-contacts/network/choosing-network-mode-for-my-mobile-phone/

Settings > Mobile data > Network Mode
If you select GSM / WCDMA auto, your mobile phone automatically switches between 3G and 2G provided you're within range of a 3G network.

Is it the way to get the PagePlus 3G only plan to work on an HTC One M8? And is this software switch on all M8's?

Thanks.