However you can still use a If-Then to step through a sequence and then enable outputs based on the sequence value at the end.
If the action is based on a sequence, then a sequence makes sense. For example, if level is between A and B, and goes to between B and C, the next step is starts, but if the level goes back between A and B, we don't go back to the previous step, but stay in the current step, a sequence
If the action was determine by the state of the of the system, such as level between A and B, then using a sequence complicates things. Using Flag to indicate a state may make sense. Like in the 4 line example, the Active state isn't needed, and the logic could be done in 3 lines, but it might not be as easy to follow.
Valve33 := Valve34 := Pump:= Auto & not Alarm & (Level > Low)
Valve60 := Valve61 := Auto & not Alarm & (Level > Low) & (Level < Med)
valve50 := Auto & not Alarm & (Level > Medium) & (Level < High)
My suggestion was more pointed to the practice of using If-Then on Boolean assignments.
IF (Thirsty and Have_Water) then Take_A_Drink := True
Else Tank_a_Drink := False
or
IF (Thirsty and Have_Water) then Take_a_Drink := True
IF (Not Thirsty) then Take_a_Drink := False
IF (Not Have_Water) then Take_a_Drink := False
It is much simpler and more direct
Take_a_Drink :=( Thirsty and Have_Water)