I think there may be a mismatch in the data in the excel, probably because two weeks were very similar in terms of sMerit:
27/08/2018 .. 02/09/2018 -> 3.186 sMerits
20/08/2018 .. 26/08/2018 -> 3.763 sMerits
13/08/2018 .. 19/08/2018 -> 3.767 sMerits

The reading is still the same regardless: New all-time minimum and a decreasing trend...