Respected Sh. Kasturi Sethi ji,
For sake of better clarification, Clearances which are Exempted from whole of Duty of Excise under SPECIFIC JOB WORK notifications are not to be included for determing Turnover of ₹ 400 Lacs.
Specific Job Work Notifications such as 214/86-CE dt. 25/03/86 or 83/94-CE dt. 11.04.94
May be I would have missed out some provision... Would look forward for knowledge update.
SSI has option for duty payment for the job worker activity done for manufacturer. Same does not fall under 214/86, hence your view point to that extent holds good.