Thanks in advance for any help,

I am new to Airtable and to using formulas at all. Having trouble figuring this one out, but I’m sure it’s a simple solution.

Context:

I grow mushrooms, 3 different strains (K, B, L). Every day I prepare a new batch (8 bags, same strain). Every week I prepare 5 batches, 1 batch per day, mon–fri.

I need to create a unique record for each batch. Currently, I am using a concatenate formula to combine the strain code (K, B, or L) with the week number it was created. i.e. K.40

My Problem:

2 days of the week, I will repeat the same batch (strain type) I did earlier in the week, which leaves me with two instances of the same thing (K.40).

I need a formula or combination of formulas that can identify when the same batch code has appeared twice in one week, and then assign only the second instance of that occurrence with a (.2) i.e. K.40.2.

See screenshots below for reference:

Screen Shot 2020-10-05 at 17.25.41|700x451

Any help is appreciated,

Thanks a lot