Equal Favorites Vs False/True Favorites

At what point does one draw the line using price variation between the 2 equal favorites ?
Assuming they are both True Favorites
On scale, percents vary depending, so 2.00 and 2.30 may show 30 cents
but if it's 3.00 and 3.30 respectively, it's a different percent value when calculated, yet it's still 0.30 cents.

Debatable ?