How do I make this script go both up and down?

So I have this script to CFrame a model, but no matter what I change the y values to it won't go back up after it goes down. It goes down both times. help?

while true do
    wait()
for i=1, 5 do
    wait()
    f:SetPrimaryPartCFrame(CFrame.new(f:GetModelCFrame().p) * CFrame.new(0,-.2,0))
end
wait(5)
for i=1, 5 do
    wait()
    f:SetPrimaryPartCFrame(CFrame.new(f:GetModelCFrame().p) * CFrame.new(0,.2,0))
    end
end