are deductible.  

We have a copy of a memo written from Kirton & McConkie 

Here's an exerpt:

"The Energy Policy Act of 1992 added language to section 162 which tightened up the "away from home" test.  Now, section 162(a) reads:

    For purposes of paragraph (2), taxpayer shall not be treated as being temporarily away from home during any period of employment if such period exceeds 1 year.

Thus it would appear that our missionaries, by the clear language of the statute should no longer qualify under the "away from home" test if they are gone for more than one year.  However, when the Energy Policy was pending in Congress, we lobbied against this provision.  While unable to "stop the freight train," we did manage to have Congress include language in the Committee Report to the effect that this new Code provision was not intended to change the "away from home" test as it applied in the context of charitable service.

      The conference agreement treats a taxpayers employment away from home in a single location as indefinite rather than temporary if it lasts for one year or more.  Thus, no deduction would be permitted for travel expenses paid or incurred in connection with such employment. As under present law, if a taxpayers employment away from home in a single location lasts for less than one year, whether such employment is temporary or indefinite would be determined on the basis of the facts and circumstances. This change is not intended to alter present law with respect to volunteer individuals providing voluntary services to charities described in section 501(c)(3).  (102 H Rpt. 1018 Part 3; Conference Report (To accompany H.R. 776) Section 9705. Transfers.)

Based on the foregoing, we have continued to advise couple missionaries that they do not fail the "away from home" test merely by reason of being out fo the missions for 18 months or two years.  However they should understand that there are other elements of the "away from home" test that they also must meet."

And this is where we get into the importance of couple missionaries retaining their former home.