If a very recent TER review states a rate, let's say $$.5/hour, but the provider's agency's website states something different, e.g., $$$/hour, should I assume TER is correct?  What's the best way to confirm the rate without triggering the provider's LE alarm?

If you're contacting a girl through her agency, you must assume their information is current. The recent review may be by a long-time regular who enjoys an older rate, or called the gal directly as an independent.

If you are seeing the rate in the provider profile (not the review) it probably needs to be updated. Submit a Problem Report on the profile page, sighting where you saw the new rate using a link.