Is it Okay to turn off a Laars Endurance for the summer?

I have a two family house and a Laars Endurance feeds two bathrooms and two zones of base board heat in the upper part of the house. The Laars stores boiler water in a 20 Gallon buffer tank(for heating only) at 180 degrees 24/7. I'm thinking this is a waste of energy.

The Lochinvar Noble NKC 199 feeds two bathrooms and three zones in the downstairs part of the house. I recently added a bypass that connects the hot water lines between upstairs and downstairs and wanted to use the Lochinvar Noble which would only turn on on a call for hot water and not keep. The Lochinvar is prett powerful and seems to keep up with demand no problems. Is it ok to turn off the Laars Endurance until October November and use the Lochinvar?

This would allow me to do some maintenance on the Laars like clean the Flat Plate and inspect the tank etc -and when winter approaches I'll close the bypass valve and let the Laars take control of the upstairs heat and hot water. (I may replace it with a smaller Noble but I'm not sure yet)

Or should I just keep them separate?

As always I appreciate the guidance!