I know meters in general can have a 20% variance from the "true" number when testing blood. Hopefully someone with more experience will chime in soon! 
She's already eaten because I Test, Feed, & Shoot so after I tested she was starving because it was @ 6-6:30p & she hadn't eaten since morning breakfast with exception of possibly grazing on wet food left out that she or housemates didn't finish because I wasn't home. Then tested a @ 4-5 strips total & none were within range. I called Walmart because according to them that means they are defective and they reimbursed me after asking me a series of questions about them. I don't know what to follow anymore, even my vet said they've never used control solution in her hospital but yet the ReliOn meter instructions strongly encourage testing with control solution every time you get a new meter or new strips for accuracy. I didn't want her to miss a dose after starting it almost a week ago & to me that's an emergency because I don't know if they have withdrawal attacks like missing other certain meds or wtf. So since her PMPS was above 200 (although possibly inaccurate) & her dose so small (.50) & she'd just eaten alot & exhibited no hypo symptoms, I gave her the shot because I had waited almost an hour for a reply (understandably, it's Fri. night, here in the states at least) & knew you're supposed to skip the shot after a certain period of time if you're too late (have the time written in my notes somewhere) so I was frantic. She's acting normal at least so fingers crossed. Thanks
I thought I read somewhere you can shoot up to an hour after feeding...Is it only 5-10 min.?! And as for the stalling: doesn't that lower the BG, thus making hypo more possible once shooting? Sorry, I'm a newbie. Still so confused. I've since given her the shot after so many replies about no one else relying on control solution and based on her SS & she did ok through the night, but just for future ref. would like to know. Thanks