Assisted locationing (GPS)?

We are having issues trying to turn on assisted GPS on the TC55. In the regular place for Location options on Android has the two higher performance modes grayed out, leaving GPS the only available option.
What needs to be done for these options to become available?

There are options for something called Xtra GPS, which upon looking into it, appears to be assisted GPS, but there is no documentation available on proper using it.

It Xtra GPS same as Assisted GPS?

Is there anything to be done in application to use it or just turning it on makes applications use it?

How we may verify this function works?


The device model is TC55AH

The OS version is 4.4.3 (Build 02.52.02)