withQueueWatermarks always throws exception

Following code snippet:
{{
int lower = 10;
int upper = 20;
return SocketAcceptor.newBuilder()
.withQueueWatermarks(lower, upper)
.build();
}}

always ends up with exception:

{{
11:15:17 Caused by: quickfix.ConfigError: invalid queue watermarks, required: 0 <= lower watermark < upper watermark
11:15:17 at quickfix.AbstractSessionConnectorBuilder.withQueueWatermarks(AbstractSessionConnectorBuilder.java:58)
}}}

Method withQueueWatermarks should verify parameters instead of class fields.