No, there will be a slight difference when different wood is cut, especially when switching from softwood to hardwood.
You will need to make a test joint with the new wood and then make a very slight adjustment of the jig to tighten or loosen the joint fit depending on the hardness of the wood being cut. This adjustment will involve moving the guides back or forward just a little, usually about 1/4 - 1/2 of a line graduation. It isn't much, but it makes a big difference in how well the joint fits. You shouldn't need to make any other changes to the jig. You are almost there.
It takes a bit of practice to learn how to make good dovetails, and using cheap wood for learning is a wise decision. If you get some poplar or other of the cheaper hardwoods to practice with your settings will be closer when you switch to other hardwoods, but there will still be a difference. Keep notes of these positions for each type of wood and bit, so you don't have to make as many test cuts in the future when you want to cut the same wood and joint again. The more dovetails you make, the easier it will be to do this without making test cuts. When you can get very close on the first setup you can go ahead without the test cuts and just do some fine tuning in the first joints of your work. Every professional sometimes needs to make test cuts for setup. It's part of the job, but it can be minimized with more experience.
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