Systematic observation in educational research highlights a wide diversity of aspects of classroom interactions, yet frequency of score cycles is crucial when analysing dimensions of classroom teaching. The aim of this study is to focus on differences in quality of teaching and loss of instructional time using Classroom Assessment Scoring System--Secondary Manual with fifteen-minute score analysis and five-minute score analysis. Video data are collected from five English as a foreign language lessons with one teacher in addition to an interview with the teacher. Data is collected in a Norwegian lower-secondary school. The lessons are analysed with both the standardised and novel approach. Results suggest that the five-minute score analysis produces a more accurate account of the phenomena of study. Instructional time is lost for more than 5 min on two occasions after further examination of the CLASS-S productivity dimension due to an instructional pattern of finishing lessons early. Paradoxically, the interviewed teacher emphasises lack of time for the facilitation of student learning as a limiting factor for own teaching.