Long running time at job

I try to launch QSVM algorithm (from Qiskit example ) on all real quantum devices (that is IBM Q) and get running time 5-30 seconds on one job. But if I use ibmq_qasm_simulator, I get 5-20 ms (not always) on one job. I want to show comparison of time by QSVM and SVM for Big Data and I must use only real quantum devices (for QSVM). My friend did similar work and he got little running time on quantum device (ibmq_16_melbourne) in september (but It doesn't work today - the same longrunning time). What is changed?

If you run a circuit with just one shot (shots = 1) then you will find that it uses less time than if you use 1000 shots.