No
A hydrometer that agrees with a Francis Freas hydrometer is a proven good hydrometer. About one in 35 EZ Red hydrometers screws up and arrives with acceptable accuracy.
Pb permeabilty and natural circulation of electrolyte precludes rapid accurate density readings. With large cells like mine I stop charging at 1.254 and 2 hours later cell readings are 1.260 Tropical density electrolyte. Yes. Tenperature corrected. This is for charging. Moderate discharge rates generate little heat.
If you want to be snotty, record 30 minute interval voltage readings to second decimal point throuhout the test. Add the numbers then divide by number of samples. Do exactly the same with amperage samples. This will give you a median average value to work from.
