Starting the clock - clarification

[kentref]

From the NFHS casebook, page 20, 3.4.2 Situation D:

K11 punts the ball from a fourth and 10 situation. R1 catches the kick and returns 10 yards. During the down, but prior to the catch, K3 holds R2. R accepts the foul. RULING: After enforcement, the clock starts on the ready-for-play signal. (3-4-2b3)

First question: Does it make any difference, in terms of when the clock starts on the next play, when K's foul occurs? Does PSK figure into this in any way (in terms of the clock status)?

The NFHS Rules Study Guide has the following statement:

When administration of a penalty is one of the reasons for stopping the clock, the decision to start the clock is made on the following principle: the clock should start just as it would if the foul had not occurred. The one exception is an accepted penalty for delay of game, after which the clock always starts on the snap.

Why does this principle not apply to the aforementioned caseplay?
In other words, if the holding foul had not occurred it would be a new series for R and the clock would obviously start on the snap.