Ah, right, this is Robert Howie of Meikle Drumgray as witness to John Storry taking possession in 1761 of the lands after his father-in-law's death as provided for in the marriage contract a quarter of a century before. I also have a transcription of the same 1761 sasine.
The 1710 document mentions three Robert Howies. This one in 1761 cannot be No 2 because the 1710 document refers to No 2 as deceased. No 3 was born after 1689, so his father No 2 must have been born no later than about 1670, so No 1, who was the father of No 2, cannot possibly still have been living in 1761.
So this has to be either No 3 at a ripe old age or (No 4) Joseph's son Robert who was born in 1720 at Meikle Drumgray. No 4 married Janet Main of Ballochney around 1750-ish, and all their children were born at Meikle Drumgray between 1754 and 1768. The baptisms all refer to their father No 4 as 'of' Meikle Drumgray rather than 'in' Meikle Drumgray, which does imply that No 4 was the proprietor.
So did No 3 die without issue, and the land passed to Joseph? And if so, was Joseph really illegitimate or was he descended from another son (or even a brother) of No 1?
I do have quite a lot of sasines still to look at, some of them written by a particular clerk in Lanarkshire who might as well have been writing upside-down in Chinese while intoxicated for all the sense I can make of them.