1. script. to put simply with an example transaction requiring multi signature would take longer since you have to sign it multiple times with multiple keys.
2. your hardware. and how much of it you are using. for instance whether you are using CPU or GPU and whether you are using 1 core or multiple,...
3. the cryptography method that the coin is using. it is not always elliptic curve and it is not always the same elliptic curves. different methods have different times. also among ECs they are not all using the same curve. those using 256 bit curves will have 256 bit keys and your calculations will be done on that size numbers. a bigger curve like the 521 ones will take longer and the smaller curves like 192 and 224 bit curves will be faster. i believe one of the bitcoin forks changed the cryptography while talking about post quantum computer thing so that is something to consider.
4. the code that you are using for signing. there is not only one method of signing using Elliptic Curve. there are multiple ones and also depending on how they are coded it can take longer or faster to create a signature. for instance libsec256k1 is super fast but other libraries such as using openSSL is much slower.
p.s. as others said you are not stress testing the coin, you are bench-marking your hardware with the conditions i mentioned above.
thanks for the answer