Custom Calendar Best Practice - Custom Hierarchy Sort By

Good morning,
I've developed a custom calendar that groups by a given WeekNum on the month, based on how many working days of the belonging Week belong to the month, even if it appeared to me that the calculation process seems over-complicated 

TargetMonth_Algorithm = 


SWITCH(TRUE(),

'Calendar'[Working Days in Week]='Calendar'[Max Working Day Week] , MONTH('Calendar'[Date]),
'Calendar'[Working Days in Week]<'Calendar'[Max Working Day Week] && [IsMaxWeekNum]=1, MONTH('Calendar'[Date])+1,
'Calendar'[Working Days in Week]<'Calendar'[Max Working Day Week] && [IsMinWeekNum]=1, MONTH('Calendar'[Date])-1,
'Calendar'[Working Days in Week]>'Calendar'[Max Working Day Week] && [IsMinWeekNum]=1, MONTH('Calendar'[Date]),
'Calendar'[Working Days in Week]>'Calendar'[Max Working Day Week] && [IsMinWeekNum]=0, MONTH('Calendar'[Date])-1,

MONTH('Calendar'[Date])+1)

In other words somehow, I managed to carry out the prementioned;
Now I have the following problem, I've created a custom hierarchy with :
Year -> TargetMonth (which is the algorithm month format "mmmm") --> weeknum 
But unluckily I cannot display with the sorting that I would like.

I could concat MonthNum & MonthName and the sort would be working, but I would just like to sort the hierarchy based on the MonthNum column without including it in the hierarchy.

Best Regards