Good callout. The weeks only line item is used for the combo chart. So you're choices are two. You can just use the planning period filter instead or add the formula to be the same. But setting to TRUE is not correct. You only want the planning weeks.
Weeks Only? is something I was playing around with. Not needed for L2. Sorry for the confusion on that one. I use it as a filter so that I see weeks only without months in the way. But it shows all weeks. You need just the planning weeks.
In SYS00 there should be a Line Item that is Boolean formatted and is editable. This will serve as the months you want in your planning view.
In SYS01 there is a Boolean line item that references the line item in SYS00 using the MONTHVALUE function. This will set the BOOLEAN to true for only the weeks that fall within the Months you selected in SYS00
On the New UX page use the line item from SYS01 to filter your weeks.
For reference, you can see the blueprint in the screenshots I provided above.
Many thanks @JaredDolich finally got it to work per your suggestions. Key one was referencing the Planning Period Filter Weeks Only to Planning Period Filter. Seem a bit counterintuitive at first but the difference is the latter is formula derived and retains the month while the latter is just the weeks. Kind of wondering how that happens but am guessing its because the Time Scale is Week - is that correct?
The MONTHVALUE formula in the line item Planning Period Filter somehow retains the month even though the Time Scale is Week - does that make sense?
And as you had suggested I changed the Summary Method for Planning Period Filter to 'All'.
Thanks for being so patient with me as well, Jared. Sometimes it takes a few iterations but most of all we solve what we set out to do with some persevering 🙂 Much to learn with Anaplan, lessons learnt with every misstep.