Calculation on my investment return in Steemit world.

It has been quite a while since I had signed in. But the excitement I get with my involvement in Steemit never tappers off. Now is the time for me to pause and evaluate the return of my investment in Steemit. Time is money, some wise man has said so. But how much is your time worths? Let us refer to :
http://www.fool.com/investing/general/2015/01/18/how-does-your-income-stack-up-against-the-average.aspx . For simplicity, I will use US$ 25 per hour rate in my calculation below.

(1) Upvoting return:

Based on my own research, if you spend four hours reading and do upvoting, you can upvote about 40 times, 5 time every half an hour and by doing so, it is not going to hurt your voting power too much.
Four hours give an money value of US$ 100 (US$25 x 4). The curation reward I get from upvoting in the past is on average 0.001 SP per upvote. Thus, 40 upvotes will give me a total of 0.04 SP or US$ 0.08.
Therefore, my return for upvoting works out to be 0.08% 。[ = ( 0.08 / 100) x 100 % ]。

(2) Commenting return:

Without any calculation, I can conclude that commenting produces a return % lower than 0.08%. Why? Firstly you need to spend more time in reading the post plus all the comments that followed. Secondly, often auther ignores comments and leave them unanswered. Personally I found rewarding comments is rare with few exception.

(3) Posting return:

I spend about three hours or more for each posting cycle which includes planning, research, drafting, fine tuning on presentation and inserting images, etc. The equivalent of money in investing my time is US$ 75 (= 3 x US$ 25 ) for each post. For the past 20 posts which I submitted, I get an average posting reward of 34.36 SBD or about US$59.76. Therefore, my posting return works out to be 79.68% [ = ( 59.76 / 75 ) x 100 % ]

In conclusion:

(1) Upvoting and commenting returns are ridiculously low. My Steem power ( 280 SP at the moment) is just too low to be able to produce any meaningful return.
(2) Posting has a decent return. However, it is less than 100%, meaning my earning in Steemit is lower than an average worker in America. Part of the reason is that the SBD / Votes ratio for my posts is fairly low in comparison to other authors. Why? I do not know. The only consolation I get is I can work at my own pace and free time, unlike in the real world, I need to be present at work site and have a boss breathing down my neck all the time.

Have you ever evaluated your return in Steemit?

Do you agree with with my calculation?

Please upvote and make comment. Please correct me if I am wrong.

Thank you and have a wonderful day!

Image credit goes to Guest (Wallpaper 2) at Steemimg