The ambiguity of Accomplishments with ‘chāyīdiǎnr’ (almost) is due to the fact that an Accomplishment is a complex event and logically contains an inchoative (which describes a process of ‘becoming’) and an endpoint or a result, as a result normally requires a process leading up to the result. The ambiguity of ‘chāyīdiǎnr’ with an Accomplishment is caused by the function of what the adverb ‘chāyīdiǎnr’ modifies, or more technically, what the adverb has in its semantic scope. It may have within its scope either the inchoative process itself (I nearly began writing the letter), or the result (I almost reached the resultative state of ‘finished’ it) With the RVC, however, the adverb ‘chāyīdiǎnr’ (almost) only takes the scope of the resultant state of the event, but not the process, as shown:
*Tāmen chàyīdiǎnr gài hǎo yī zuò fángzi, kěshì méiyǒu gài.
(Int: *They almost finished building a house, but they didn’t start building at all.)
Tāmen chàyīdiǎnr gài hǎo yī zuò fángzi, kěshì méi gài wán.
(They almost finished building a house, but they didn’t finish.)
(1a) is ruled out as ungrammatical, because with an RVC, the adverb ‘chāyīdiǎnr’ can only refer to the result, that is, the result is short of being reached, it cannot only negate the process involved in the event. Hence (1a) cannot be followed by a clause negating the implementation of the action. This is because in the RVC, the meaning of result is already integrated into the process, therefore, whether the adverb ‘chāyīdiǎnr’ includes within its scope the process or the endpoint (result), it always refers to result. On this point we see the difference between the RVC and an Accomplishment verb phrase.
 Loar, J. K. (2011). Chinese syntactic grammar: functional and conceptual principles. New York: Peter Lang.