Buy Rent sell cost comparison

Hi Guys

I'm trying to compare costs options so we can make a decision what is the best way both financially and lifestyle wise. i crunch some numbers so it is easier to look at, see attached spreadsheet. However I’m not sure if my calculation and rates are correct (Formulas, Rent, Tax, depreciation, interest), i'm seeking your advice, experience, knowledge to help out review the options in-terms of Tax, legal and Financial calculation (don't hold you for it) and let me know what do you think? as well if you have a better and more accurate to do this task such as spreadsheet that will help a lot.

Few points I wasn’t sure:

• Can we claim for depreciation on renovation?
• If we claim rent working from home, do we need to pay Capital Gain Tax?
• Is the calculation I have done are correct?
• How do i calculate Tax % for calculating the Rent Tax gain or loss?
• Work from home % - Do I calculate is base on the rent rate? If so 30% is reasonable?
• Can we claim all/most Reno expensed for the company - Reno due company office?

Notes & Thoughts

• I have used IO both for refinance and IP(Investment Property) loan.
• Reno - we have two option 4bd 235k or 5bd 435k.
• We calculated out annually expenses are 100k excluding mortgage repayment on PPRO+IP.
• If this calculation are correct it looks more likely option 3 is appealing.
• I have based the property purchase price 80/25% Bank/Deposit+Stamp duty percentage
• Ruff figures (rent, tax, Reno, valuation…etc) just to be in the ball park.
• me and my wife will be investing but i have put the % on 1 investor ATM.

Please let me know if you you have any questions,

Thank you