Slice group coding using Flexible Macroblock Ordering (FMO) based on Macroblock (MB) importance in H.264/AVC has been studied for providing higher error robustness in error prone environments. However, the efficiency still needs to be improved and the high computational and time cost it causes remains to be an issue. In this paper, an Adaptive Macroblock-to-slice Allocation map (MBAmap) Updating scheme is proposed based on our previous research work. The extra computational and time cost introduced is less than 10% compared to the conventional methods. The PSNR of the reconstructed video at the decoder side can be improved for up to 0.6dB compared to previous proposed method. A Slice Matching (SM) error concealment method is also introduced, which increases the PSNR for a further 0.2 to 0.4dB when applied with the slice group coding scheme.