MF, i am sorry but you have bought into the biggest scam to ever hit lawn care.
Again, I am sorry to say that it probably won't touch your bindii problem, however you are in a sample group where it may have some affect. I will make a bad problem better but won't anywhere near solve it.
The main problem with it is the high amount of water going on at the same times as the herbicide simply washes it off. In my opinion, one way of potentially helping it is to put a decent dose of a naturally based surfactant in the spray bottle with the scotts mixture. A decent squirt of something like earth choice washing up liquid would suffice.
you have paid $25 for 42g of mcpa and 7g of dicamba, a bit of NPK and iron. thats where they get you
For next time (to really take out the bindii):
apply granular fertiliser eg
https://www.bunnings.com.au/garden-basics-2-5kg-lawn-fertiliser_p0282394 for $5
wait 1 week
12.5g of dicamba and 75g of MCPA
https://www.bunnings.com.au/yates-500ml-bindii-and-clover-lawn-weedkiller-concentrate_p2961541. This will do 330 sqm for $9
liquid fertiliser for $10
https://www.bunnings.com.au/garden-basics-2l-plant-food-concentrate_p0276187sprayer
https://www.bunnings.com.au/aqua-systems-5l-garden-pressure-sprayer-kit_p2960992Apply the liquid fertiliser with the old weed and feed sprayer, spread the granular one as even as you can by hand and spray the weeder with the sprayer. Its time consuming and annoying with the manual sprayer but it is dead easy to knock up a walk behind sprayer with a few parts and an old edger frame (or even garden trolley)
As an example, I have been looking after next doors lawn (gone away for 2 months). Ever since it was installed in 2017 they have had bindii and oxalis/clover. I put down 60g/sqm of baileys 311, and followed up a week later with a spray of buffalo pro - all weeds knocked dead inside of 5 days.
I honestly hope it works for you - it definitely will have some improvement but no miracle