[Kraftwerk]

I have noticed some of the Taylor and Ilco -'off' brand oem keys measure thinner than their factory counterparts. If you use a caliper on the flat metal stock you can get a reading on it ~ there is a difference. That causes differences as well in the 'performance' of the key.
Keep you original key, the one that came with the car, in a safe box only take it out when you are making copies of your key and use high quality blanks. Make sure the key -cutter 'stamps; your key with their logo so if its cut wrong you can take it back and have anew one cut. (In this case you tend to eat the cost on the blank if you brought your own blanks, alas.) So you want to use a locksmith who knows what they are doing.