This has happened to me on a number of occasions. Ceramic or Porcelain......to the customer it’s just a tile. To the tiler it is more cost in addy, blades/hole cutters and cutting time. Saying that, I have always told the customer the extra costs, but have never charged them extra. This is partly in the hope of repeat business from the customer (not yet happened) or a tip at the end of the job (not yet happened). No more Mr Nice guy. Next time I will charge them extra. You have to explain & justify the extra costs/time. I don’t know what your porks are like, but some of my previous customers porcs really added an extra 5-10 mins cutting time per tile. Cheers Sean