you can ask them if they would like to pay by the year (leap years are a bit more) & pro rate for the month, day, hour, minute second & nanosecond for maximum accoutabilty( ha ha)or

to avoid a potentially time wasting situation, charge them  a flat fee + $$ for each addl owner in the chain for the 25 yr period with a cap not to exceed ?? whatever. we can save you $$ for the very simple searches & recoup our time spent for the bad ones, py