In the wide shot of the clock on Ralph's wall (above the headboard), the time is just before 8 o'clock - which matches the time on the time clock (where Sam is about to clock in). The close-up of Ralph's clock jumps back to 7:45.
When Ralph clocks in, he drops his time card into the top of the clock. When the 8 o'clock whistle blows, both cards (Ralph's and Sam's) are in the 'In' slot below the clock.
When the whistle blows at noon (lunch hour), the time cards are both in the 'In' slots. When it blows at 1:00 (end of lunch), both cards are in the 'Out' slots. The cards should have been in the 'In' slots when the whistle sounded at both times.
When Ralph Wolf is floating over Sam with the seven balloons, he is at or near neutral buoyancy (neither rising nor falling appreciably). After Sam pops six of the seven balloons, Ralph is still near neutral buoyancy. With six of the seven balloons gone, Ralph should have sunk (or fallen) down to the ground.
After the 5 o'clock whistle sounds, Sam indicates it is too close to quitting time - when it is actually after quitting time.