UPDATE: I spoke to IRS about this issue. The agent said that filing 2555-EZ did NOT constitute a revocation of the Foreign Housing Exclusion. He was clear that I could take the Foreign Housing Exclusion in 2018, even though I had last taken the FHE in 2013 by filling the 2555, while in subsequent years, I had only filed 2555-EZ (without formally revoking the FHE). He said that in general, filing a simpler version of the form should not (and would not) constitute an (accidental) revocation.
