Actually, the recovery tank is reasonably accurate.
If you look at the level in the tank with the engine/coolant cold and then warm, you will find that the level warm is over 30% higher than cold. Said another way, you are "changing" coolant in the reservoir every three times you drive the coach.
Is checking in the reservoir as accurate-- no. Is it accurate enough-- yes.
Another BIG caution. The test strips are quite time sensitive. Using an expired strip will likely give erroneous results.
And, if you are tired of checking and adding SCA's, switch to one of the new generation OAT-based coolants. If you have a Caterpillar, I suggest Caterpillar ELC. If Cummins, the equivalent product from Fleetguard (Cummins brand). 6 year life with no checking and no adding unless you drive over 300,000 miles and then just add a "booster" after 300,000 miles.
