public boolean isWorthAddingWithoutLoss(final String var, final String newValue, @Nullable final String oldValue) {
        final VariableMap.VariableState state = getState(var);
        //if new value is blank, it is not worth adding
        if (StringUtils.isBlank(newValue)) {
            return false;
        }
        //if there's a new value but not an old value, then it IS worth adding
        if (state == null || StringUtils.isBlank(state.getFormulaString())) {
            return true;
        }
        //if the previous parsing value is known and it is identical to current value, then it is ok to overwrite the old value with the new one
        return oldValue != null && oldValue.equals(state.getFormulaString());
    }
Returns true if the given 'newValue' for the given variable 'var' can/should be added without overriding existing info in list
main/src/main/java/cgeo/geocaching/utils/formulas/VariableList.java