Thank you all for your responses.
First, I know better than to have called it a jackplate. Sigh. The stern bracket on which the motor is mounted.
Second, my boat, 2520 SCXL, has a solid transom - that is, no cutout for the motor. Stern is full width with fish box all the way across. Motor on stern bracket. I have contorted my fat old body as far possible into the hatch that is on the center line of the boat and just in front of the transom. I can see where the electrical line from the existing Lenco tabs comes from - but not where it comes through the hull because that entry point is beyond one of the longitudinal stringers. I can reach under the stringer and back up a ways but still can't touch where the electrical line on the Lencos comes in. With the Bennet tabs I have to insert the nipple through the transom, attach an ell on the inside and then attach the hydraulic hose with ferrule and nut and tighten things up. This will be on the inside of a hole I won't be able to see and may not even be able to reach.
I would have thought the 2530 would have been very similar. The pictures that warthog posted show the nipple entering the boat and I can't figure out how he could even have seen that spot if his boat is like mine.
Please, more advice for the newbie!