Dear Pradeep,
Swamy's book can't have information which is not available with DoPT itself. There are 3 OM's which deal with the matters of second time benefits. All should be available on DoPT website.
Ministry of Home Affairs OM No. 36034/27/84-Estt.(SCT) dated 02/05/1985
Ministry of Home Affairs OM No. 36034/21/87-Estt.(SCT) dated 07/11/1989
DoPT OM No. 36034/6/90-Estt.(SCT) dated 02/04/1992
Among these 2nd one is most important as it supersedes 1st.
Its main content is "it has been decided that the provisions contain in this dept OM dated 2.5.1985 shall not apply to those ex-sm who have been re-employed by Private Companies/Autonomous Bodies/Public Sector Undertakings/Govt offices on 'casual/contract/temporary ad hoc basis and who can be removed from such service at any time by their employer'"
So the word 'probation' is not used anywhere in any OM as even DoPT failed to reply whether probation comes under temporary category or not. As per informal information from previous SSC Chairman, in SSC's opinion, the day an Ex-SM joins any govt./PSU/PSB job, he looses his reservation for any further job. As i mentioned earlier, matter can best be decided by courts of law.
the 3rd is abt age relaxation after joining civil jobs.