ComEd residential overhead drop wire from a splice and not from a utility pole

Hello,
I have a 100 amp overhead service connection, that spans 140 feet between the ComEd utility pole and a overhead service mast connection.
The mast was recently replaced to be a new 2 1/2 conduit mast, with permit and approval from the local inspector.

ComEd has said the current connection between the service mast to their utility pole crosses the neighbors property, and it therefore they are going to change their overhead dropwire connection location. That's fine. until they said they do not plan on installing a new utility pole, but rather they intend to "splice" the new dropwire connection to their line, which will be approx. 100 feet away from the nearest utility pole in either direction.

The residential service mast connection point is 12ft. from the ground, and the overhead ComEd line where they will attach is sagging low. only 15 feet off the ground.
I am concerned that this plan of connecting a 100 foot drop line to a splice and not to a pole, will put additional strain on my service mast when they attempt to tighten the line slack to be no less than 10' 6" from the ground at the lowest point.

Is a inline splice common, or should a utility post normally be installed for this situation?