Today, 3D subband (3DS) video coding schemes are close to current standard solutions in terms of coding efficiency while they add the scalability functionality through embedded bitstreams. Spatial scalability may be regarded as a key-feature brought by such codecs, enabling adaptation to varying terminal capabilities and display sizes. However, this functionality still suffers from a lack of coding efficiency when motion compensation is used. Though enabling motion compensation at the temporal filtering stage dramatically improves energy compaction, it generates a strong motion vector overhead and introduces a reconstruction drift when decoding at lower spatial resolutions. This is because the Discrete Wavelet Transform and the motion compensation (MC) are not commutative. Some authors solve this problem by transmitting the drift signal as side information, but this increases the bit-rate. In this paper we present a low-resolution optimized MC-3DS scalable codec with no drift, that does not generate any overhead. Its structure is fully compliant with any subband-tree entropy encoder and preserves all the other scalability functions (temporal and SNR). Tests and simulations show that the new scheme remains quite efficient when decoding at full resolution, while it outperforms the previous solution as far as spatial scalability is concerned, especially with high-activity sequences.