Focomat V35 split grade with color head (again)

Hello everyone,

Several threads exist on the matter of split grade printing with Focomat V35 color vs vario-contrast heads, and conclusion seems to be that both methods should generally work.

Now, here is my puzzle. I just got second-hand V35 with color head (in fact, with VC head too, but sadly it needs repair), and was projecting filter grades using adjustment table from Ilford (https://www.ilfordphoto.com/amfile/file/download/file_id/1933/product_id/733/). I also got a very old set of Ilford under-the-lens filters and was comparing the colors I get with under-the-lens filter vs color head at various grades. I notice substantial difference, especially at middle grades. Say, Grade 2.5 Ilford filter seems to have a lot more magenta than color head produces on corresponding table-based setting (see attached photos).

Would it be a valid method to "calibrate" and come up with my own table based on ILFORD under-the-lens filters? Any other practical suggestions, e.g. could it be that color head needs repair too? (although it looks to be in perfect condition)

Will appreciate any advice.

- Alex