We are not affiliated with the government
An Independent View of Social Security
Please seek consultations on this, but indications are that deferred compensation would not be subject to the "earnings test".
From http://www.ssa.gov/pubs/10063.html :
If you get Social Security and your total yearly earnings exceed the limit and these earnings include a special payment [e.g., deferred compensation], you should contact Social Security. Tell us you think you received a special payment. If we agree, we will not count the amount of the special payment as part of your total earnings for the year.
From http://www.ssa.gov/OP_Home/rulings/oasi/43/SSR73-30-oasi-43.html :
Further held, such wages [deferred compensation], since wages, since earned prior to retirement, are not subject to the post-retirement work test and thus may not reduce the worker's retirement insurance benefits.