Note the different note values of the 7 stroke rolls in US notation (8a), Berger notation (8b), and Zündstoff notation (8c).
8a (US) and 8b (Berger): Not dotted 8th notes that are counting in the bars note value.
8c (Zündstoff): Dotted 8th notes that are not counting in the bars note value.
Therefor, and to comply with the 2/4 time signature, some of the flams are written as 4th instead of 8th notes.
“The two words ’information’ and ’communication’ are often used interchangeably, but they signify quite different things. Information is giving out; communication is getting through.” (Sydney Justin Harris, 1917-1986)
Society of International Rudimental Drummers