hit a snag

Well the cardy is sooo nearly ready for seaming up, but I have hit a snag with the sleeves. I'm definitely no expert, but the pattern in the mag seems a bit umm.. dodgy? I've posted across a couple of boards to get some advice on how to read it, but apart from some comments on how it's written badly and is contradictory and unclear, no-one can tell me exactly what it should say! Creative Knitting haven't updated their website either, and some rumours suggest there may not be a next issue.. hence the 'snag'!

The sleeve pattern seems simple and is knit flat. I've increased 2 stitches every 6 rows and now currently have 60 stitches on the needle. My next instruction, according to the pattern, is:

"cast off 2 sts at the beginning of the next 2 rows until 30 sts rem, then every row until 20sts rem. Cast off."

There's lots of stuff wrong with this sentence, and I just can't get my head around it. I can't imagine have step cast off for the decreases, and it doesn't match the back or front shaping either.. So if any lurking geniuses can interpret please let me know!