Councillors have agreed to continue with the four-and-a-half day week in primary and secondary while collecting further evidence of its effects on school attendance and parents.
Nursery staff, however, will be forced to revert to a full day on a Friday after complaints from parents.
It is has been an open secret that Liz Reid, the city's departing director of education, wants to end the current organisation of the school week, to free time for staff development.
"We are out of step with the rest of the country," Mrs Reid said. The asymmetric week had to be placed against the backdrop of the Government's standards agenda. Absence levels tend to be higher on Fridays than other days and parents of nursery children complained about the difficulties in the varied length of the school day. They want five normal sessions.
Teacher unions opposed any move away from a system that creates earlier starts, longer mornings and early closure on a Wednesday or Friday. Pupils spend the same time in school but their days are uneven.
The Association of Head Teachers in Scotland says benefits include allowing parents to arrange appointments such as "doctor or dentist visits, haircuts".
"We are afraid if this time is taken from us, then the momentum and motivation for development work will stop and staff will lose interest, it being extremely difficult to work up enthusiasm to plan the implementation of new initiatives after having given one's all to a whole day's work in class," heads maintain.
The Educational Institute of Scotland says there are strong arguments for having planned activity time in "quality time" and not at the end of the working day, a point echoed by the Scottish Secondary Teachers' Association.
The EIS says the asymmetric week helps pupil concentration, which is better in the mornings, and shifts teaching time from afternoons. The half-day blocks off time for after-school clubs, extracurricular activities and supported study.