Many of the designs we tat could be done with different size rings. In fact people have often viewed a piece of lace, and not having the pattern they have worked out an approximation to make the same design. At some time later they come across the original pattern and note that although the original and their copy don't use the same stitch count, they both work. Sometimes though, the ring size is integral to the design like the tatted sea shell below.
Edited to add. The shell pattern is from the Tatted Lace Pattern Collection newsletter and is no longer available.