SRAM to Shimano cassette change, limit screw adjustment?
Last night I replaced the cassette on my road bike. I went from a SRAM 11x26 9 speed cassette to a Shimano 12x27 9 speed cassette. There was a spacer on the backside of the SRAM cassette and I moved it over to the same location on the Shimano cassette in order to get the new cassette reasonably tight. It was very wobbly without it. I was surprised that I needed substantial adjustments to the limit screws. Without the adjustment, the chain shifted right off the high end (smallest cog) and wouldn't reach the low end (largest cog) of the cassette. Is that normal? If not, is there anything in particular that I should check?
To complete the picture: the wheels are Mavic Cosmos and the new cassette is Ultegra. I'm not sure what level the old cassette was. I replaced it (and the chain) at the advice of my LBS who said the middle cog on the old cassette was worn out, but didn't have a replacement cassette in stock. (It's a small shop.) This is the first time I've done this on my own.
Thanks for any help.