I doubt that any kit manufacturer will divulge their kit mix. I owned a commercial winey and investigated the issue you are struggling with. First question do any of your labels use a varietal name to describe the wine or are you using a fanciful name? IF varietal then the formula request is valid as it must state on the label the percent content. if a fanciful name and a designation as a table wine then a formula should not be required.
I used an outfit called US Elite Winery Supplies, which I believe is owned by one of the kit suppliers, who sells kit wines at quite a discount and will provide a certificate of validity that the varietal content sated for the kit is 75% of the kit juice. I would use the varietal name on the label as it conforms to the 75% rule and kept the certificate on file along with the batch details in the event of a audit.
I visited with a winery in Indianapolis whose entire wine supply was kits. he followed the fanciful name concept.
another problem you may have is one individual approved your initial labels and another has come along and over ruled the first individual, which means to me that an interpretation is going on. if you can get them on the phone maybe you can resolve.