Putting 10 of those lights together would give you 18k theoretical lumens. However, human perception is a funny thing. For instance doubling light output (or sound for that matter) doesn't lead to double the perceived intensity. More like 1.4x the intensity according to some.
If you're talking photography you will realize twice the brightness with twice the power, so for the same shot you would be able to adjust by a full stop with twice the lumens. However, in order to increase distance you will need to account for the inverse square law which you can roughly approximate by quadrupling the output for double the distance.
Also, because of losses in optics (unless they are bare LED) and dimming of the LEDs due to heat you might not be getting the advertised output of your light. Some manufacturers advertise the theoretical lumens output straight from the LED, some places estimate the actual output, and others actually measure the output. Still others just seem to ask their marketing department for guidance.
Hope that answers your questions.