ΔE 12.3, fair: the same colour family, but not a straight swap. Ivory RLM05 is noticeably lighter, cooler than Panzer Yellow.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Ivory RLM05 is noticeably lighter, cooler than Panzer Yellow.
The same difference applies the other way round: Panzer Yellow is noticeably darker, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Panzer Yellow on the colour wheel See Ivory RLM05 on the colour wheel
All matches: Panzer Yellow equivalents · Ivory RLM05 equivalents