Correct, oil doesn't seal bent valves.
The valves are not necessarily bent, they may be burnt.
If the pressure had evened up after putting oil in, then that would indicate worn rings.
You can see the oil has temporarily sealed the rings in all the cylinders by the slight rise of pressure, but as there is still a similar difference in pressure between the two pairs, (slightly higher on the two 'good' cylinders), that sugguests valves.
Valves don't bend on they're own, either a slipped timing belt (cause the valves to bend), or a high miler (burnt valve seats).