Frozen plan and increase in AB for increase in cola

Thank you, as always, for all the insights.

1 . A Frozen DB Plan, owner and wife only (owner only plan).

2. Plan frozen after 12 31 2017

Avg comp at 12 31 17 was 117,000.

Formula was 10% of avg comp for each year of service. 

3. Had 6 years of service and 2 years of participation at 12 31 17.

4. As of 12 31 2017 the AB based on percent limit was $5,850. As his avg comp was 117,000 and this was reduced by 6/10 (as had 6 years of service at 12 31 17. (10% of avg  comp of 117,000 for each year of service was the formula at 12 31 2017 then frozen)

5. As of 12 31 2017 the AB based on the dollar limit was $3,583, since the 2017 415 dollar limit of 215,000 was reduced by 2/10 to reflect the 2 years of participation as of 12 31 17.

6  . Therefore his benefit at 12 31 17 was limited to 3,583 (lower of the dollar or the percent limit).

7 Question...if this frozen plan allows for increases due to increases in the COLA..

then

A. for 2018 would his AB be 3,666? (As the 415 dollar limit went up in 2018 to 220,000 and 220 reduced by 2/10... as had 2 years of participation as of 12 31 17 when frozen..

B. If the AB for 2018 is indeed 3,666 is this shown as an increase with a TNC or the the AB for the FT ( ie AB as of 1 /1/ 2018,) is simply increased and no TNC?

C. As the dollar limit goes up each year, would the AB keep going up annually until it hits the percent  limit  of $5,850 that he had as of 12 31 2017?

Thank you very much