The amount of memory required by perfect hash functions at retrieval time is one of the primary issues to be taken into account when looking for such functions. This paper gives empirical evidence about the effectiveness of a strategy that is suitable for significantly reducing the memory requirements of the order-preserving minimal perfect hash function proposed by Z.J. Czech et al. (Inf. Proc. Lett., vol. 43, pp. 257-64, Oct. 1992).