Is the first format of Play the Percentages considered the same show as the last format of Play the Percentages?
I'd say yes, because it's the same show but with a different format. You could probably ask the same question of a show like Wheel of Fortune. It's played much differently today than it was in 1975, but it's still the same show.
True, but the format change in PtP was pretty dramatic. In the second format, you weren't taking guesses at the percentages anymore; they were outright given to you in the form of "X percent of people got this question wrong". So it was kind of a stretch to say that you were playing the percentages — what you were really playing was
Twenty One plus four.
Wheel, on the other hand, has always kept the core elements of Hangman with a wheel, despite whatever window dressing it gets.