I don't know what others have told you, all I can tell you is from my own experience. I've adopted several diabetic cats over the years. Each one has their own normal way of acting. I take their normal into consideration when I get their BGs. For example, when Tucker(GA)'s BGs were high he was cranky, when they were normal he was content, when low he was very hungry and talkative, sort of agitated. For Kiki, if she's starving for food she's either too high to too low, but if she's cranky and hungry, she's too high, nice to me and hungry, she's too low.
Use the meter as your guide, but watch your whole cat and take notes because six months down the road you wont remember if at 210BG was their a belly ache that day, head scrunching or meatloafing. Was he overly hungry or just fine. Water bowl staying filled or empty every day. Those are the things that are going to help you feel more comfortable in the future.
I remember the first day Tucker did not sit with his head resting on the water bowl, I felt like screaming for joy. I think his numbers were still unregulated, we were on Humulin back then, but I remember feeling so happy about that positive change. Changes in personality, whether good or bad are indicative of something. Watch those changes and make notes, it's sort of like a treasure hunt, the more information you gather, the better your answers will be in the end. Share that information with your vet, make copies of your data for their records.
I'm sorry, I'm not trying to lecture or anything, just want to share with you that there's more to this than just numbers. The fact that you are hometesting is awesome and in time this is going to become routine for you and hopefully you wont be out of your mind with worry. Remember to enjoy your cat through all of this.