Another interpretation for you:
I have always assumed that the CTR endorsement meant you can operate (depart/arrive) from a controlled aerodrome where you don't continue into any adjoining CTA (ie you depart/arrive directly into Class G) as you just depart and don't need to make any further calls generally.
However, things get a little complicated when we talk about Class C, as in most cases you are identified and receiving a control service and at the boundary you will be given a "control service terminated" etc. The procedures in a Class C CTR are essentially the same as CTA. Landing at class C, you need to request a clearance well in advance rather than just reporting and heading in via an approach point. Most RPL holders with the CTR training won't have touched class C aerodrome procedures.
So I now take it to mean that CTR endorsement allows you to operate from a class D directly into class G. If you want Class C aerodrome, you need the CTA endorsement.