As a consulting engineer, I have a question. Is the entire house settling at the same rate? 2X10’s @16″ should be Ok for a 12-foot span. Is the wall that is overtop of the other beamshowing any cracking in plaster, drywall etc. It’s hard to believe that one beam settles and the other doesn’t. I used to own a 50-year old house but yours is a new problem. Adjsuting the kitchen floor may not fix the problem.
I recommend the house mover or maybe an Engineer to examine the structure. Good luck!