Price Difference in Ticks

If, maximum tick difference between the back and lay price, constant mtd is set at 5.
What condition do I use to ensure the bet doesn’t happen if mtd is greater or smaller?
Would I be correct also to assume a tick is 0.1 for example 2.11 and 2.30 is a 2 tick
difference? Or to be more precise 1.9 tick difference

Hi
g_ticks(price1,price2) returns the number of ticks between price1 and price2.

example:
and selections trigger expression g_ticks(back_price, lay_price) is equal to 5
will ensure the trigger only executes if there is exactly a 5 tick gap between best back and best lay price.

Table of Befair price tick increments below:

Price        Tick increment size  
1.01 to 2     0.01
2 to 3        0.02
3 to 4        0.05
4 to 6        0.1
6 to 10       0.2
10 to 20      0.5
20 to 30      1
30 to 50      2
50 to 100     5
100 to 1000  10

Hi, I just don’t seem to be able, for some reason, to grasp these ticks, here are two example of the sort of prices I am using back 2.00 lay 2.24 and back 1.91 lay 1.98. Would those gaps be 2 and 7 ticks respectively? So if I want to cover both I could use g_ticks(price1,price2)<7.
Thanks Mike

Hi
If you refer to the above table you can see Betfair prices move as follows:
in the range 2.00 to 3.00, each tick is 0.02 e.g. 2.00, 2.02, 2.04, 2.06 .....
in the range 1.01 to 2.00, each tick is 0.01 e.g. 1.50, 1.51, 1.52, 1.53 .....

if we look at your two examples:
g_ticks(2.00, 2.24) = 12 ticks
g_ticks(1.91, 1.98) =  7 ticks

so if you want to make sure the gap between best back price and best lay price is equal or less than 12 ticks:
and selections trigger expression g_ticks(back_price, lay_price) is equal or less than 12