--> Automates a lot of your expense tracking --> Much cheaper than most softwares/fancy sheets --> Will probably save you a couple of thousand extra on your taxes if you follow all the recommendations. 

Code § 7701 - Definitions, my understanding is that the answer is NO, but maybe I am wrong.As the actual rate of withholding is 15% of the sales price, and as the refund (if any) would be "within 90 days", it can be a major setback for my company´s flipping cash-flow because 15% is way higher than the taxable income (and of course than the tax itself), so we would be in the necessity of capital injections to flip the next properties.If any of you have comments on this, it would be very helpful.Thanks in advance

Rather than taking out some boot from your sale to pay off debt, you could take a detailed look at your financing math after buying a new property and then strategically refinance to replace expensive debt with cheaper debt, but this is not very easy in today's rate environment. 

Sometimes, cheaper isn't better.

I do my own taxes so I can see my taxable income reduced every time I add a property into the tax return form.

Generally taxes will be lower on the smaller/less expensive properties at a greater rate that the rents will be cheaper, if that makes sense.Hope that helps.  

Near-term taxable income redux is the objective.  

Judge said: “However, an activity that involves the use of tangible property is not a rental activity if "[t]he average period of customer use for such property is seven days or less" in a taxable year (short-term rental).

There are cheaper one’s in D/F areas but I would be careful as those can create a laundry list of additional issues.

If you choose a cheaper fix now, keep a close eye on things to ensure no new issues pop up.