Explanations regarding the romanization of he-he-dalet-yod-resh, the Hiphil of he-dalet-resh.

The word should be romanized "hehedir," because in  Alcalay's Milon 'Ivri-Angli shalem, 1964-1965, it is pointed with a sheva under the second he.  Hebraica Cataloging (on both p. 16 and p. 63) names this dictionary as the authority for identifying shevas which must be represented by the character "e" in standard ALA/LC romanization.
In this case, when we deduce from Alcalay's entry that the sheva under the second he of "hehedir" must be represented
by an "e" in romanization, we are not endorsing a theory that this sheva in  this Hiphil 3rd person singular perfect verb is "na'" and not "nah."  We are simply following the guidelines in Hebraica Cataloging for determining  the correct romanization of a sheva-- that is, to romanize a sheva as "e" if Alcalay prints it.

We use and recommend the romanizations which follow from the guidelines  in Hebraica Cataloging in order to maintain a standard which can be imitated by anyone who consults and follows the same guidelines. Most cases covered by the guideline making Alcalay the authority on romanization of sheva concern loanwords from other languages into Hebrew.  We hope to give further consideration to the possibility of excluding  native Hebrew words from its scope.

Concerning the possibility that the sheva printed in Alcalay's  "hehedir" is a typographical error, it should be noted that he consistently  punctuates this and a few other Hiphils and Niphals from first-he roots  with a similar sheva in other editions of his dictionaries, both  Hebrew-English and Hebrew-Hebrew.