LoadTest Assertion using small Total Runs Limit

Hello,
I am using SoapUI Pro 4.0.2 version.
Load Test details:
Threads:1
Strategy: Simple
Test Delay : 0
Random : 0
Limit: 1 (Total Runs)
Assertion details:
LoadTest Assertion : Step maximum
Minimum Requests : 1
Max Time : 50
Max Errors : -1
The thing is that "Step Maximum" assertion newer fails even if the maximum test step value exceeds 50ms.
But when I change Test Runs Limit to 3 or above this assertion works as expected: it posts error to the LoadTest Log.

Regards,
Sergey.