5. B precedes the later codd. in spelling κολακειας—its favourite itacism (-ει-). Etymologically -ει- is correct, the noun being derived from κολακευω: cf. βασιλευω, βασιλεια; see Winer-Schmiedel Grammatik, § 1Th 2:13 c, for this point of orthography.
The omission of εν before προφασει is based on Bאc 17 39 47, against all other witnesses—an attestation scarcely decisive. The shorter reading might be preferred, intrinsically, as the more difficult; on the other hand, as Weiss observes, the familiarity of the bare (adverbial) dative προφασει (pretendedly: cf. Php 1:18) would tend to the dropping of the preposition.