Calculating a play-off handicap

Can anyone with knowledge of handicap allowances for play-offs please help with the following question:

In the event of an 18-hole medal competition (held by our golf society) finishing in a tie, we have decided we will play a 3-hole playoff (with lowest net score over the 3 holes to win).

The R&A advise as follows regarding a playoff handicap: http://www.randa.org/en/Rules-and-Amateur-Status/Rules-of-Golf.aspx#/rules/?ruleNum=10.%20How%20to%20Decide%20Ties

This explains you allocate a 'playoff handicap' based on percentage of the holes being played, so in this case 3/18ths of your normal handicap. My question is whether this should be 3/18ths of the difference between the players in the playoff (method one), or 3/18ths calculated for each player, with separate rounding for each player (method two).

There is a difference as follows:

Method one - with a 9 handicapper and a 13 handicapper - full difference is 4; 3/18ths of difference is 0.67, which is rounded to one shot allowed for the 3-hole medal play-off.

Method two - same players as above, but 9 handicapper gets 3/18ths of his handicap (which is 1.5 rounded to 2) and the 13 handicapper gets 3/18ths of his handicap (which is 2.17 rounded to 2) and therefore there is no shot allowance for the 3-hole play-off.

Thanks to anyone who can help!

As its a strokeplay event then the handicap should be calculated accordingly, hence method two is used.

Thanks Brian

It says "the percentage of 18 holes played should be applied to the players’ handicaps ..." not ".. applied to the difference between the players’ handicaps