That 1-2-6-18 places staking plan came from E.I.
1st. bet 1
2nd. bet 2
3rd. bet 6
4th. bet 18
Total 28
You stop, then start again as soon as you strike a place getter.
You should have 6 banks of 28=168 .

You will win on some runs & loose on others. But that does`nt matter, its the overall profit we are after , this is called sequence betting.

Have you thought about ignoring TAB No.1 all together & starting at TAB No.2 & down.
Quite often No.1 is at low value, if ever they get up .Its rare that they pay well therefore poor value & best ignored all together.
You will probably find that you have missed some very good payers because your selection was No.1 in that race & the other got up instead.

__________________
Cheers.