Now we are getting closer to the truth! The end of FY is coming and you figured you got money left in the kitty, so you asked the various departments if they had things they may want to purchase, didn't you? (Don't worry! Been there, done that!
What we were told before for such situations ( and I hope Armyvern chimes in, she is the expert) is that if the items are totally unrelated, and in fact could have each been the object of their own separate LPO, then, you should issue a separate LPO for each item or set of items that would be considered a separate purchase, but at that point, it is irrelevant that you chose to go and purchase each one at the same time, or even from the same provider. In such case, each LPO is its own separate amount for application of rules purpose. Very important though: It must be justifiably separate items
and then, you have to get separate quotes for each based on each value. In other words each one is treated as a separate purchase and the records must show it.
This goes further than which department orders it. In your example, if the various items requested by the deck department could have been the subject of separate LPOs, then you should go that route. For instance if their "$600" is made up of say, a $250 small boat tool kit, then $200 set of racks for storing oars (do we still use those?) and finally $150 for a new trailer jack, then each one of these is unrelated to the others
and could have been made at a different time without regards for the others. The fact that you chose to go out and buy them at the same time, even from the same provider, is irrelevant so long as all the proper paperwork for each separate purchase is kept straight.