Hi @I_T
Welcome to the forum 
Regarding the concepts themselves:
- Virtual Users are an emulation of a user performing your script. You can consider them to be an execution agent which has loaded your script and its context and is responsible for running it. They load your script and run it, that’s it. In practice, if you ask k6 to run N VUs, it will make sure to spawn N concurrent components running your script repeatedly; effectively simulating N users performing the behavior you described in your script repeatedly.
- Every time your script is executed (by a VU), that’s what we call an iteration. An iteration is always performed by a virtual user. Keep in mind that an iteration can produce different outcomes and take a different amount of time depending on what your script performs, though.
As a result, you can customize the behavior of k6 in pretty interesting ways, as you’ve already discovered, using scenarios. You can ask k6 to essentially have N virtual users running your script M times, and customize how those actions are distributed using different executors. For instance, the shared-iterations executors will make sure that a total of exactly M iterations are performed, and k6 will spawn up to N virtual users performing iterations until M is reached. Each executor basically implements a specific strategy that defines k6’s behavior when it comes to execute iterations using virtual users.
I hope that clarifies a bit more. Please let me know if you have further questions on that front 
Regarding your script, would you be comfortable sharing your test script (anonymized, of course)? I have tried running the simplest example I could think of using your configuration and didn’t reach the same output.
Here’s my test script and full output for reference:
import http from 'k6/http'
export const options = {
scenarios: {
contacts: {
executor: 'ramping-arrival-rate',
timeUnit: '1s',
preAllocatedVUs: 10,
maxVUs: 200,
stages: [
{ target: 5, duration: '2s' },
{ target: 15, duration: '10s' },
{ target: 20, duration: '5s' },
{ target: 0, duration: '10s' },
],
},
},
thresholds: {
http_req_duration: ['p(95)<60000'], //units in miliseconds 60000ms = 1m
http_req_failed: ['rate<0.01'], // http errors should be less than 1%
checks: ['rate>0.99'],
},
}
export default function () {
http.get('https://httpbin.org')
}
Results in
running (26.4s), 000/010 VUs, 292 complete and 0 interrupted iterations
contacts ✗ [====================================>-] 000/010 VUs 26.4s/27s 02 iters/s
✓ checks.........................: NaN% ✓ 0 ✗ 0
data_received..................: 2.9 MB 111 kB/s
data_sent......................: 31 kB 1.2 kB/s
http_req_blocked...............: avg=11.98ms min=180ns med=400ns max=441.07ms p(90)=450ns p(95)=558ns
http_req_connecting............: avg=3.82ms min=0s med=0s max=116.03ms p(90)=0s p(95)=0s
✓ http_req_duration..............: avg=128.15ms min=109.55ms med=116.71ms max=528.09ms p(90)=132.79ms p(95)=218.37ms
{ expected_response:true }...: avg=128.15ms min=109.55ms med=116.71ms max=528.09ms p(90)=132.79ms p(95)=218.37ms
✓ http_req_failed................: 0.00% ✓ 0 ✗ 292
http_req_receiving.............: avg=67.05µs min=36.54µs med=60.96µs max=461.22µs p(90)=84.11µs p(95)=91.64µs
http_req_sending...............: avg=48.1µs min=26.31µs med=43.4µs max=146.69µs p(90)=61.09µs p(95)=81.94µs
http_req_tls_handshaking.......: avg=8.03ms min=0s med=0s max=291.22ms p(90)=0s p(95)=0s
http_req_waiting...............: avg=128.03ms min=109.46ms med=116.62ms max=527.97ms p(90)=132.68ms p(95)=218.23ms
http_reqs......................: 292 11.05812/s
iteration_duration.............: avg=140.21ms min=109.61ms med=116.85ms max=562.37ms p(90)=146.97ms p(95)=362.92ms
iterations.....................: 292 11.05812/s
vus............................: 10 min=10 max=10
vus_max........................: 10 min=10 max=10
Cheers 
