The point of my comment was that extraneous information, information obtained by means other than seeking the evidence for a particular case, is inappropriate.
To get to the point of the benefit of the doubt, I think the expectation of exactness is not as great with a tribunal as it is with a civil or criminal court. In other words, we often hear of cases being won or lost on technicalities and so on. Tribunals can have a somewhat more relaxed view of the evidence presented to them than the courts have, and that applies generally to tribunals. It doesn't mean that any old thing that's said in a witness' statement is acceptable, but the tribunal members have the opportunity to weigh what they hear and determine whether it is reasonable and likely to be true, and apply the idea of benefit of the doubt to that evidence, and give the appellant the benefit of the doubt for the evidence provided.
It's not loose, but it is somewhat less stringent than it is in civil and criminal courts.