processing order issue between tagValue and tagFormat

[eseb63]

Hello,
I don't understand the result i got for the test below.

I initially used 2 tags for works :

• the WORK tag for "standard" works having one or two levels by example (with GROUP for work) :
  • one level : Beethoven violin romance (work alone)
  • two levels : Beethoven Symphonies (work > movements)
    
• the OVERALL_WORK for works having 3 levels by example operas :
  • Carmen (work > acts > scenes) with GROUP for acts
    

WORK and OVERALL_WORK are mutually exclusive.

I prefix works with their composer.

I configured minimServer like this :

• itemTags : Work, Overall_Work
• indexTags : Composer-Work
• tagFormat : Composer-Work.indexFormat={$composer^^ : $Overall_Work$Work}
  

minimServer handles this fine.

I then thought it would be handy to add another way of browsing, for works often recorded as part of cycles :
by example, i would like to find albums containing the first Chopin ballade (so i need to tag the ballades individually) but i also would like to find albums containing the 4 ballades.
for this, i use a WORK_SET tag.

Test with Perlemuter release of the 4 ballades + 2 polonaises:

• each ballade/polonaise has a WORK tag
• each ballade has a "4 Ballades" WORK_SET tag
• itemTags : Work_Set
• tagValue : Work.Merge={Work_Set}
  

According to the documentation, tagValue processing is done before tagFormat, so i thought WORK_SET would be added to WORK, and then indexFormat would use all WORK tags to create Composer-Work tags.
but it doesn' work:

I expected when works browsing :

• Chopin : 4 Ballades
• Chopin : Ballade no 1
• ...
• Chopin : Ballade no 4
  

I get :

• Chopin : Ballade no 1, 4 Ballades
• ...
• Chopin : Ballade no 4, 4 Ballades
  

How to explain this?