Lamar Advertising (LAMR) represents .06 % of the portfolio yet added to their position by 2.79%
Lennar Corporation Class B (LEN.B) represents .01 % of the portfolio and they added to the stake by .03%
So, my question is: why even bother with these tiny stakes? And to add/trim these positions seems like child play : )

I have no knowledge, but a speculation: These are perhaps small positions inside some division's pension plan. Shares held in the pension plan of a small business that has been acquired, perhaps. Small changes to those position sizes may be related to odd stuff like changes in reporting, changes in managerial control, spinoffs, stock dividends, changes in whether shares are "votable" or not. Maybe even correcting the occasional rounding error.

I mention managerial voting control because that's what the 13F is for, it isn't for the firm to disclose its portfolio composition to the public. That's just a side effect for the armchair quarterbacks like us. It excludes non-US companies, options, and I believe some positions without voting power. It includes shares for which the manager has voting control but for which the common shareholders do not have any beneficial interest.

Like you, I doubt that anyone at head office would bother allocating capital at that level of size and precision.

Jim