Superior Development
Exchanges (1 of 2)
Point Count Chess, NO. 131, p186
Tartakower v. Capablanca, 1924
Any Tempos that are gained, from developing a Piece, are wiped off the Tally of Developed Pieces, if that Piece is involved in an Exchange.
H&MS go on to say that: "If one piece has moved more often than the other, its disappearance represents a loss of one or more tempos."
At first, it may seem like the outcome is a fair and even exchange of Pieces. But, the difference occurs if one Piece takes more turns in order to carry out the trade  those extra turns impact on the Tally of Developed Pieces, which could result in their army ended up "behind" in the race to develop their Pieces, ready for the Middlegame battle, and the opposing side would claim an advantage for Superior Development.
Read on, to see how Exchanges affect the Tally of Developed Pieces ...
Exchanges (1 of 2)
My Analysis
Position #1, My Analysis
PCC, p.186, No. 131, after 8...dxc4
After: 1.e4 e5 2.f4 exf4 3.Be2 d5 4.exd5 Nf6 5.c4 c6 6.d4 Bb4+ 7. Kf1 cxd5 8.Bxf4 dxc4
So, in this example, we'll see how Exchanges affect the Tally of Developed Pieces, and as a result, the battle for Superior Development ...
Exchanges (affect the Tally of Developed Pieces), After: 1.e4 e5
Exchanges (affect the Tally of Developed Pieces)
After: 1.e4 e5 

Exchanges (affect the Tally of Developed Pieces), After: 2.f4 exf4
Exchanges (affect the Tally of Developed Pieces)
After: 2.f4 exf4 

Exchanges (affect the Tally of Developed Pieces), After: 3.Be2 d5
Exchanges (affect the Tally of Developed Pieces)
After: 3.Be2 d5 
White is first to develop a Piece (3.Bf1e2); Black chooses to develop another Pawn (3...d7d5). 
Exchanges (affect the Tally of Developed Pieces), After: 4.exd4 Nf6
Exchanges (affect the Tally of Developed Pieces)
After: 4.exd4 Nf6 
White's move of a Pawn, with Black developing a Piece, enables Black to even things up, on the tally. 
Exchanges (affect the Tally of Developed Pieces), After: 5.c4 c6
Exchanges (affect the Tally of Developed Pieces)
After: 5.c4 c6 
Both sides develop Pawns, which doesn't affect the Tally. 
Exchanges (affect the Tally of Developed Pieces), After: 6.d4 Bb4+
Exchanges (affect the Tally of Developed Pieces)
After: 6.d4 Bb4+ 
Black now takes a oneTempo lead, having developed a Piece (6...Bf8b4+), as White developed a Pawn. 
Exchanges (affect the Tally of Developed Pieces), After: 7.Kf1 cxd5
Exchanges (affect the Tally of Developed Pieces)
After: 7.Kf1 cxd5 
I've not added to White's tally, for the move of his King  my reason: it's not a "developing" move; White hasn't moved the King to develop it to a good square, but to flee from the attack by Black's Bb4. White has now voided his option to Castle. (I think that's how it works; it's probably what H&MS did, here.) 
Exchanges (affect the Tally of Developed Pieces), After: 8.Bxf4 dxc4
Exchanges (affect the Tally of Developed Pieces)
After: 8.Bxf4 dxc4 
White pulls level in the Tally, as he develops a Piece (8.Bc1xf4), while Black's just moves a Pawn. 
Exchanges (affect the Tally of Developed Pieces), After: 9.Bxb8 Nd5
Exchanges (affect the Tally of Developed Pieces)
After: 9.Bxb8 Nd5 
Both sides lose a Tempo, moving a Piece that's already developed. So the Tally stays at two Tempos each. 
Exchanges (affect the Tally of Developed Pieces), After: 10.Kf2 Rxb8
Exchanges (affect the Tally of Developed Pieces)
After: 10.Kf2 Rxb8 
Black develops his Queen Rook, at the same time as capturing White's Bishop, to complete the Exchange. 
White's misjudgment stems from his belief that he's just swapped one Minor Piece for one of his own (Bishop for Knight). But, what he's actually done is spent two Tempos to Exchange a Piece (Black's Knight), which hadn't moved  Black didn't spend any Tempos to exchange his Knight for White's Bishop ...
Added to that, Black completes the Exchange by developing a Piece * (his Queen Rook), which helps him jump into a twoTempo lead, in the Tally of Developed Pieces.
PGN