No, it doesn't necessarily mean that Wellyhead. Officers, AIs and SSIs are not paid for normal parade nights. They only get paid for certain weekend training and annual camps.
In theory though, yes you could also join the ACF or CCF as an adult at the same time as serving as a TA soldier. And yes you would be eligible for additional pay for these Cadet Force duties. Anyone thinking that being in the TA will get them an express route into the Cadet Forces is mistaken - the application process will be just as rigorous (or unrigorous in the case of the CCF) as for any other applicant.
Then what is the point - whilst it is comendable that we "volunteer" our time and experience - the MoD needs to wake up - I get more in an hour than a Maj does daily - happy and always will be to give back - did do for 3 years at 34 CCT NI - however the old saying stands "money talks"