The ability of the relativistic ab initio model potential approach with explicit local exchange to produce oscillator strengths in agreement with Dirac-Fock (DF) data is tested for some transitions in silver and gold isoelectronic sequences. It is shown that all three model-potential approaches used, which differ in the local approximation for valence-core electron exchange, yield individual oscillator strengths mostly within 10% of the accurate DF results. The agreement with available experimental data is also discussed.