If numbers drop low, drop fast, or simply drop into a range that your cat isn't used to, there's a good chance you'll see what we call a "bounce." This means that the numbers drop and then spike back into a higher range. The lower numbers cause a stored form of glucose along with counterregulatory hormones to be released and the numbers bounce up. Bounces have a protective quality to them but are really annoying to the caregiver. It can take a few days for the bounce to clear.
I'd encourage you to review TR. You may also want to post on the Lantus board since there are more members there who use TR and they can help guide you.