It's also a case of you not answering a direct question that proves you wrong. If your method works, you should be able to use it to come up with a correct answer in any instance. In this instance, we know the correct answer already. This hand is a favorite. Now, show me how to use your method to reach that correct answer.
If you can't do it, it proves your method is flawed.
TBH I really dont know what you are on about, largely because I don't think you really do either.
The villain has not gone all in, so you are faced with 3 decisions
fold
call
raise
you have 15 outs... count them, list the .. whatever. 9 hearts 3 threes 3 eights.
Now you are not drawing to the nut flush so the 9 hearts should be reduced to 6 to account for this. In total you have 12 outs. which translates to just under 3:1
The pot is 24.5BB and you are faced with a call of 20BB
your 12 outs mean that you are getting 1.25:1 (not enough for a pot odds call)
However we feel that the villian has committed himself to the pot meaning that should you hit he with shove the remaining 20BB
Therefore your call of 20BB stands to win you a pot of 44.5BB if you hit on the turn. So you are being offered implied odds of 2.25:1
Really this is not quite enough, but its close and if you increase your outs to 15, it is marginally good.
If you call the flop bet the pot is now 44.5 The villain is expected to shove his last 20BB so the pot becomes 64.5BB and you have to call 20BB giving pot odds of 3.25:1 meaning that you are getting slightly more than the 3:1 required to call so its an easy call.
The slight mistake of calling the flop bet is cancelled out buy the slight increase in odds on the turn.
The only issue is why has the villain raised so large on the flop?is it that he may fold the turn if a scare card comes (one of your outs)
If this is the case then you don't really have the required implied odds to call as pot odds offer you just 1.25:1 not the 2.25:1 that were implied.
To remove this possibility raise him all-in. At this point he is definitely pot committed, he has to call.
If you call, then there is no way that you can fold on the turn as just explained but there is still a possibility that he may. The all-in prevents this and ultimately has you putting the same amount of money in as you would otherwise.
You have to consider the hand in this way rather than simply assuming that you have 30 outs because your opponent has not raised all-in.