Paul is basically doing his "thing" here:
In several of his epistles, he quotes verses from the OT which originally spoke of YHWH, but then replaces the name with Lord and applies it to Jesus. Since he was individually approached by Christ, this must be what he wanted Paul to do.
The classic examples are in Heb 1, where words originally addressed to the Father, are put into his mouth, as he addresses his son.
There are other examples in Isaiah, which the NWT deliberately alters so it appears to refer to their sock puppet, rather than his sidekick.
I remember a former dub, who ended up being chased by the elders because he spoke of jesus too much. As they said "you sound like a born again Christian."
I think it was Little Toe who once gave a talk where he deliberately omitted the nam Jehovah for the first 10 - 15 minutes. The tension in the audience became palpable, and when he uttered the magic word they almost sighed with relief.
I know a dub on street work approached a woman who asked "Are you a Christian?" the answer? "NO. I'm a jehovah's witness."
HB