On page 44 it states players can only push the roll one time. This talent however, allows the dwarf to be the exception to this rule, and push rolls more than once... and thereby allowing increased successes to pile up.
Let's use the SNEAK skill as an example. Our brave Dwarven PC wants to sneak by some very alert, very dangerous guards... so it will be a difficult sneak attempt. He rolls and only gets 1 success... but decides to push this in hopes of "sneaking better." (You can push this roll because it is more in depth than just a succeed or fail roll). He pushes... rolls appropriate dice... and gets 1 more success, but also a bane (-1 to AGILITY). In total, our daring Dwarf has 2 successes... but he isn't sure if that will allow him to get past these vigilant guards... So, he spends a WP activating True Grit, and pushes again. Rolls appropriate dice... and gets one more success, bringing his total to 3. Let's hope those guards don't SCOUT him...
Is that how others are playing it? Did this answer your question? Hope so... if not, I apologize.