The sort order for data in Reports was changed in TAC Vista version 5.1.7. The newest data should be in the bottom, but in TAC Vista 5.17 the newest is in the top.
When inserting a trend log to a report with period "Number of values" chosen, "Start/Stop Time" and "Period" works like they did in previous versions.
TAC Vista 5.1.7
This is an error and have been fixed in hotfix 41 for TAC Vista 5.1.7. The sort order is correct in TAC Vista 5.1.8 and later versions.
Install hotfix 41 for TAC Vista 5.1.7, or upgrade to TAC Vista 5.1.8 or later.