Uniformitarians Pretzel Themselves Using BP for Long Dates BC for Short Because Dates Would Change Nearer-Term

Using b. p. (before present) for very ancient dates (those dreamed-up millions and billions of years) while using b. c. (before Christ) for nearer-term dates causes the uniformitarians a conundrum about their nomenclature, that is how long ago should b. p. be used instead of b. c. in order that their b. p. dates need not be changed constantly as time marches on?