I use tweenservice for my stretcher system that I’m creating, after it goes down and up once, and attempts to go down again when it comes back up bottom legs don’t come up, they stay in the low position if that makes sense 
Code:
local TweenService = game:GetService("TweenService")
local function tweenModel(model, CF)
local CFrameValue = Instance.new("CFrameValue")
CFrameValue.Value = model:GetPrimaryPartCFrame()
CFrameValue:GetPropertyChangedSignal("Value"):Connect(function()
model:SetPrimaryPartCFrame(CFrameValue.Value)
end)
local tween = TweenService:Create(CFrameValue, TweenInfo.new(2, Enum.EasingStyle.Linear, Enum.EasingDirection.InOut), {Value = CF})
tween:Play()
tween.Completed:Connect(function()
CFrameValue:Destroy()
end)
end
local LowU1P = script.Parent.Low.Union1.Position
local LowU1O = script.Parent.Low.Union1.Orientation
local LowU2P = script.Parent.Low.Union2.Position
local LowU2O = script.Parent.Low.Union2.Orientation
local UpU1P = script.Parent.Up.Union1.Position
local UpU1O = script.Parent.Up.Union1.Orientation
local UpU2P = script.Parent.Up.Union2.Position
local UpU2O = script.Parent.Up.Union2.Orientation
local animation = Instance.new("Animation")
animation.AnimationId = "rbxassetid://9856348934"
animation.Parent = script
local up = true
local iswelded = false
local canmove = true
local track = nil
game.Players.PlayerAdded:Connect(function(p)
p.Chatted:Connect(function(m)
if m == "move" then
if not canmove then return end
canmove = false
if iswelded then
p.Character.UpperTorso.StreWeld:Destroy()
track:Stop()
iswelded = false
track = nil
for i,v in pairs(script.Parent:GetDescendants()) do
if v:IsA("BasePart") then v.Anchored = true end
end
end
if up then
-- go down
UpU1P = LowU1P
UpU1O = LowU1O
UpU2P = LowU2P
UpU2O = LowU2O
up = false
tweenModel(script.Parent.Bed, script.Parent.BedLow.CFrame)
local g = {Position = LowU1P, Orientation = LowU1O}
TweenService:Create(script.Parent.Up.Union1, TweenInfo.new(2, Enum.EasingStyle.Linear, Enum.EasingDirection.InOut), g):Play()
local g2 = {Position = LowU2P, Orientation = LowU2O}
TweenService:Create(script.Parent.Up.Union2, TweenInfo.new(2, Enum.EasingStyle.Linear, Enum.EasingDirection.InOut), g2):Play()
task.wait(2)
canmove = true
else
-- go up
LowU1P = UpU1P
LowU1O = UpU1O
LowU2P = UpU2P
LowU2O = UpU2O
up = true
tweenModel(script.Parent.Bed, script.Parent.BedHigh.CFrame)
local g = {Position = UpU1P, Orientation = UpU1O}
TweenService:Create(script.Parent.Up.Union1, TweenInfo.new(2, Enum.EasingStyle.Linear, Enum.EasingDirection.InOut), g):Play()
local g2 = {Position = UpU2P, Orientation = UpU2O}
TweenService:Create(script.Parent.Up.Union2, TweenInfo.new(2, Enum.EasingStyle.Linear, Enum.EasingDirection.InOut), g2):Play()
task.wait(2)
UpU1P = LowU1P
UpU1O = LowU1O
UpU2P = LowU2P
UpU2O = LowU2O
canmove = true
end
elseif m == "weld" then
if not canmove then return end
track = p.Character.Humanoid.Animator:LoadAnimation(animation)
track:Play()
p.Character:MoveTo(script.Parent.PadTp.Position)
local Weld = Instance.new("Weld")
Weld.Name = "StreWeld"
Weld.Part0 = p.Character.UpperTorso
Weld.Part1 = script.Parent.WeldHandle
Weld.C1 = CFrame.new(0, 0, 1.8)
Weld.Parent = p.Character.UpperTorso
iswelded = true
for i,v in pairs(script.Parent:GetDescendants()) do
if v:IsA("BasePart") then v.Anchored = false end
end
while iswelded and task.wait() do
LowU1P = script.Parent.Low.Union1.Position
LowU1O = script.Parent.Low.Union1.Orientation
LowU2P = script.Parent.Low.Union2.Position
LowU2O = script.Parent.Low.Union2.Orientation
UpU1P = script.Parent.Up.Union1.Position
UpU1O = script.Parent.Up.Union1.Orientation
UpU2P = script.Parent.Up.Union2.Position
UpU2O = script.Parent.Up.Union2.Orientation
end
end
end)
end)
https://gyazo.com/9802122936bc2b0e6261fa9aa84d2241
https://gyazo.com/0c5da4ced11066a7a6d4e3619e3ee241 (gif got cut off)