Variable bit rate (VBR) traffic may have a wide range of packet sizes and generation intervals. While the former can be handled in the IEEE 802.11e uplink scheduling, e.g., by adapting transmission opportunity (TXOP) durations according to backlogged traffic reports, the latter may cause packet losses if service intervals of the scheduling do not fit the generation intervals. In this paper, a scheduler that employs adaptive maximum service interval (MSI) is proposed to fix this problem, while attempting to minimize scheduling overheads.