The boiler has far and away enough burner to handle your heating loads, but you simply have to adjust the output temperatures so that your RADIATION can deliver the heat to the zones. This is an installation/adjustment issue, not a problem with the boiler, maybe the tech who is coming can get it right, or maybe not, but YOU can definitely do it yourself if you are willing to do the napkin math to dial it in. Hiring a tech to do all the fine tuning to get it to perfection is time consuming and expensive compared to taking the reins and just dealing with it.
This does not take hard math, and if you're willing to share the fuel use data and your ZIP code (for weather data and outside design temp purposes) I'm willing to take a shot at walking you through it.
A zone that isn't able to maintain the setpoint temperature is an indication that the zone has less radiation per BTU of load than the others. The simplest solution is to bump up the programmed output temperature, tweaking in the "outdoor reset" curve to a slightly higher level, taking it up 5F at a time until it gets there, then backing off a degree or so at a time until it can't, to get the maximum condensing efficiency out of it. You may find some of the verbiage in
this bit o' bloggery useful for understanding the underlying concepts of why you would do it this way. A more expensive way to deal with it would be to add radiation sufficient to work at the same water temperatures as the other zones.
The particulars of how to set the outdoor reset parameters for the
NCB 240 start on p.55.
The particulars of how to set the outdoor reset parameters for the
NCB240E start on p.80.