Recently I noted textual differences between the MT and LXX text in Isaiah. One other difference noted in our reading recently was in 1 Chronicles (translated as Supplements in the LXX) 21. From the ESV (a MT based translation):

Now the angel of the Lord had commanded Gad to say to David that David should go up and raise an altar to the Lord on the threshing floor of Ornan the Jebusite. So David went up at Gad’s word, which he had spoken in the name of the Lord. Now Ornan was threshing wheat. He turned and saw the angel, and his four sons who were with him hid themselves. As David came to Ornan, Ornan looked and saw David and went out from the threshing floor and paid homage to David with his face to the ground. And David said to Ornan, “Give me the site of the threshing floor that I may build on it an altar to the Lord—give it to me at its full price—that the plague may be averted from the people.” Lord what is yours, nor offer burnt offerings that cost me nothing.” So David paid Ornan 600 shekels of gold by weight for the site.

From the NETS (a very recent LXX translation), which because of DRM imprinting I cannot excerpt here, but go to this link (pdf) and check out 1 Supplements 21:18-27. In the first Ornan also sees the theophany (angel) that David is witnessing. In the second … he is not.

A second feature found only in the LXX  is the interesting banter/exchange passing between David and Ornan in the purchase of the threshing floor. It seems likely that it was possibly traditional in a certain style of bargaining to offer a price, have the seller insist that he would just give it, and the buyer would then pay full price disregarding the formulaic refusal. However in the LXX this passage is altered. David offers a price (in silver). Ornan refuses. David then insists he will pay in silver (which is according to formula) … and then he pays in gold instead of silver, which contravenes what I perceive as the custom via an extravagant overpayment.

This raises two questions … What do we take as meaning of David’s theophany (David it might be noted had less evident and obvious theophanic experiences than his son Solomon). Is there any change to the story or meaning that you might extract if Ornan and his sons do not witness the angel? Is there a connection to the contravention of custom in the following bargain/purchase exchange?