That's an interesting, but subtle and very specific change to the previous directions the WT have sent to congregations regarding the labelling of the contribution boxes...
You do remember the March 2017 letter??
NOW - add temporary labels over 'Local Congregation Expenses' boxes
BoE Letter, October 2, 2017 - Re: Contributions Received at the 2017 Annual Meeting
Please place temporary labels on the contribution boxes so that all boxes are clearly labeled “Worldwide Work.”
PREVIOUSLY - no label changes, just send money in 'Local Congregation Expenses' to Bethel (minus any minor expenses incurred during the actual event)
BoE Letter, March 2, 2017 - Re: Broadcast Events Held in Kingdom Halls
8. Donations placed in the box labeled “Worldwide Work” should be forwarded to the branch office using jworg. Donations placed in the box labeled “Local Congregation Expenses” can be used to cover local expenses incurred during the event. Thereafter, any surplus should be forwarded to the branch office as a donation to the worldwide work.