hi Aron,
do you mean that the formula is blank when it prints for certain records? if so, that means you've got null data coming into your report. a formula will stop if it hits a null and there is no check done for it.
if you do have nulls, you've got a couple of options...
(a) if you want to convert the null fields to default values (e.g. 0 for a number, '' for a string) then go to the Report menu > File Options > check on Convert Database Null Values to Default.
(b) the option if you don't want to convert them (some people don't because that alters the 'true' data returned as a 0 is different than a null numeric field) then you need to do a check in your formulas.try something like this...
if isnull({Tenant.UnitID}) and isnull({Units.ID}) then 1
else
if (isnull({Tenant.UnitID}) and not isnull({Units.ID}) then 2
else
if (not isnull({Tenant.UnitID}) and isnull({Units.ID}) then 2
else
if {Tenant.UnitID} = {Units.ID} then 1
else 2;