The Griner is a low band apply(LBA) valve body. My only experience is with the TA non low band apply vb. I never downshift when i slow down. I've heard that a LBA vb will jerk when shifted into first while moving. Again, no experience with the LBA type. Obviously if you slow down and then need to accelerate from a low speed, you may want to downshift. I will sometimes take off in second when driving in ice and snow. Otherwise it's not a good idea, due to converter slippage and heat.