Calendar year DB plan uses highest consecutive 48-month average. Pay history is:

May 2000-April 2001: $18,000 per month, plus bonus of $40k in 4/2001
May 2001-April 2002: $21,000 per month, plus bonus of $55k in 4/2002
May 2002-April 2003: $22,000 per month, plus bonus of $61k in 4/2003
May 2003-April 2004: $23,500 per month, plus bonus of $70k in 4/2004

EGTRRA amendment applied $200,000 limit to all prior years.

Another practioner has informed me that in rolling monthly averages such as this plan uses, you limit the pay to the annual limit in effect for the Plan year in which the 12-month period begins. Therefore, the limited FAE = $200k for each year, since all 12-month periods begin in 2003 or earlier.

Or, can final 4 months of pay average be capped at $17,083.33 ($205,000/12), meaning that final year in 48-month average is $201,667?

I basically agree except one small difference. You limit the pay to the annual compensation limit in effect for the calendar year in which each 12-month averaging period begins.

This is supported (by most people's interpretation) by 401(a)(17)-1(b)(3)(ii) and example #3 of that regulation -- and also, see Q&A #6 from the 1991 Gray Book.