How do Jehovah Witnesses explain differences between NWT and Hebrew/Latin/Greek in Zechariah 12:10 and Acts 20:28?

The bible many times attributes actions to God as if he did them directly, when it is actually that he allowed it or had someone else do it. This is similar to a foreman saying that he build a house even though he didn't even hammer in one single nail. In simple terms, these scriptures are similar to that.

Below I have quoted an old Watchtower article that explains Zechariah 12:10.

Also here is a link to an appendix to the NWT that explains why Acts 20:28 was translated the way it is: http://wol.jw.org/en/wol/d/r1/lp-e/1001060098

Watchtower 1953 8/15 p. 511 - Questions From Readers

● Zechariah 12:10 states: “They shall look upon me whom they have pierced, and they shall mourn for him, as one mourneth for his only son, and shall be in bitterness for him, as one that is in bitterness for his firstborn.” Jehovah is the speaker, and it sounds as though he was the one pierced instead of Jesus. Some argue this proves that Jehovah and Jesus are one in a trinity. So how is Zechariah 12:10 to be explained?—R. B., New York.

To avoid what seems to be a piercing of Jehovah some of the later Hebrew manuscripts read “look upon him whom they have pierced”, rather than “look upon me whom they have pierced”. At first these late Jewish manuscripts show this in the Keri, or corrected reading in the margin; but eventually in some manuscripts the change was brought up into the body of the text itself. Rotherham’s translation, on the basis of these late manuscripts, offers in a footnote “him” as an acceptable reading in place of “me”. So does the American Standard Version. Some modern translations, such as Moffatt and An American Translation and Revised Standard Version, use “him” instead of “me” in the main body of the text itself. However, the oldest and best Hebrew manuscripts read “me” rather than “him”.

As far as literal piercing is concerned, this occurred in the case of Christ Jesus, and at John 19:37 the prophecy of Zechariah 12:10 is quoted and applied to Jesus: “They will look upon the one whom they pierced.” (NW) They did not literally pierce God, who was in heaven and to whom Jesus spoke when he was on the torture stake. (Matt. 27:46; Luke 23:46) God could not die, and then resurrect himself. (Ps. 90:2) Yet inasmuch as Jesus Christ was Jehovah’s representative who became “the exact representation of his very being”, in piercing Jesus they could be said to be piercing Jehovah. (Heb. 1:3, NW) When sending out his followers to preach Jesus said: “He that receives you receives me also, and he that receives me receives him also that sent me forth.” (Matt. 10:40, NW) This shows that in receiving Jesus we receive Jehovah who sent him. In like manner, to pierce Jesus is to pierce Jehovah who sent him. It does not prove Jesus and Jehovah are one, any more than it proves Jesus and his followers are literally one. In another case Jehovah showed that to reject his representative is to reject Him. When Samuel was Jehovah’s appointed judge over Israel the people came requesting a king instead of a judge. Samuel was displeased when they said: “Give us a king to judge us.” But Jehovah told Samuel: “They have not rejected thee, but they have rejected me.” (1 Sam. 8:4-7, AS) In rejecting Jehovah’s representative they rejected Jehovah, in effect; but this did not make Samuel one with Jehovah in a trinity.

Some of those used as tools to accomplish Jesus’ impalement realized their mistake and became frightened; the crowds that had sanctioned the piercing smote their breasts when they saw their blunder, and later some involved ones repented and followed Christ. (Matt. 27:54; Luke 23:47, 48; Acts 2:23, 36-42) But the only bitterness and mourning that hit the religious instigators of the piercing was when things did not work out fully for their selfish interests. The ones who truly mourned were his faithful followers. (Luke 24:17) But as Zechariah 12:10 also foretold, about this time Jehovah’s spirit was poured out upon the faithful remnant of natural Israel, at Pentecost. So the text had its miniature fulfillment.

At the second presence of Christ Jesus the complete fulfillment takes place. His followers are persecuted and jailed and some are killed, and the work of announcing Jehovah’s King and kingdom is pierced and killed. These things done to Christ’s work and followers are counted as done to him; the persecutors are charged with piercing him. Any mourning by them is in selfish fear when they see coming upon them the dire consequences of their acts. The only true mourning is on the part of Jehovah’s people who had allowed themselves to fall short of their duties and be taken captive in Satan’s worldly system and made inactive in Jehovah’s service. But Jehovah comes to the rescue of this remnant of spiritual Israel, cleans them up, pours out his spirit or active force upon them, and under the enthroned King Christ Jesus the work is revived. (Matt. 25:40, 45; Rev. 1:7; 11:1-13) Their mourning gives way to gladness.

Hence Zechariah 12:10 cannot be properly understood to support the trinity doctrine.