Smooth shifts are what an automatic is supposed to do but doesn't always achieve. To quote an old mechanic friend of mine: If it ain't broke don't fix it.
To answer your question though. If the bands are too loose they will slip, if they are too tight the will destroy themselves. That is why this adjustment needs to be done properly.
Preventive maintenance such as adjusting bands should not be needed unless: 1. the vehicle sees rough service such as snow plowing or heavy load hauling on a regular basis, 2. extremely high milage, 3. actual slippage or other erratic shifting problems.
Most Chrysler trannys that have bands and not clutch packs use one band for reverse and low, and another for the front (kickdown / upshift). If you experience slippage I would recommend adjusting both bands as this is not rocket science, but the problem will almost always be in the low reverse band.
Here is an explanation of the clunk many of us feel when we shift into reverse. It is a little technical but I found it interesting.
There is a definite reason for the famous "Clunk" when the rear wheel drive vehicles are put into Reverse. It is designed in. When put into Reverse, an entire different hydraulic circuitry is used and the line pressure will flow to a different part of the Regulator Valve which causes the line pressure to rise. This line pressure is directed to the Low / Reverse Servo and the Front Clutch. The need for higher pressures is due to the design features of each clutch assembly. Both clutches are applied by hydraulic force and the Rear clutch utilizes a Bellville Spring, which multiplies this force. This multiplied, higher force pushes against eight mechanical levers to assure a firm application of the band without slippage. Rear Clutch pressure here can rise to 270 psi - they deem necessary to prevent slippage. The other, forward circuit design does not have this pressure range to control those shift points. The front cluch, in this circuit does not require this higher pressure because it is used only in the upshift to Drive, and since the car is already under way, there is no likelihood that there will be any slippage here. Chrysler tried to reduce this shock somewhat, but they didn't want to revise the whole thing. If you look at a cross section of the Low / Reverse Servo, you'll see the spring cushoning the piston travel as it applies the band; This lever has the Low / Reverse Band adjustment on its' end. If you loosen the adjustment to reduce the shock, the shock will become more harsh, this adjustment is not recommended. There is one aid a Chrysler dealer recommended to me, he said that they modified the circuit flow rate by adding a small Cotter Pin into the hole for this circuit in the valve body. What this did was to delay the pressure build-up , not eliminate it, but build it up slowly, and they had many happy owners with no more complaints.
I hope this helps.