Calculate A, his gross annual income after all the commissions were added.

Sipho's gross annual income is the sum of his annual taxable salary and all commissions received.

$$A = \text{Annual Taxable Salary} + \text{Commission (April)} + \text{Commission (June)} + \text{Commission (August)}$$ $$A = \text{R}518\,771.40 + \text{R}15\,260.00 + \text{R}17\,815.00 + \text{R}34\,078.00$$ $$A = \text{R}585\,924.40$$

The gross annual income is $\boxed{\text{R}585\,924.40}$.

Sipho's gross annual income is R585 924.40. According to the 2026/2027 tax table, this falls into the bracket R530 201 - R695 800.
The tax formula for this bracket is: R125 599 + 36% of taxable income above R530 200.

$$\text{Gross Tax} = \text{R}125\,599 + 0.36 \times (\text{R}585\,924.40 - \text{R}530\,200.00)$$ $$\text{Gross Tax} = \text{R}125\,599 + 0.36 \times \text{R}55\,724.40$$ $$\text{Gross Tax} = \text{R}125\,599 + \text{R}20\,060.784$$ $$\text{Gross Tax} = \text{R}145\,659.784$$

Sipho is 34 years old, so he qualifies for the Primary Tax Rebate for 2026, which is R17 235.

$$\text{Net Tax Payable} = \text{Gross Tax} - \text{Primary Tax Rebate}$$ $$\text{Net Tax Payable} = \text{R}145\,659.784 - \text{R}17\,235.00$$ $$\text{Net Tax Payable} = \text{R}128\,424.784$$

SARS has already deducted R125 053.56.

$$\text{Remaining Tax Due} = \text{Net Tax Payable} - \text{Tax Deducted by SARS}$$ $$\text{Remaining Tax Due} = \text{R}128\,424.784 - \text{R}125\,053.56$$ $$\text{Remaining Tax Due} = \text{R}3\,371.224$$

The tax consultant states Sipho needs to pay an additional R464.37 per month for 6 months.

$$\text{Consultant's Suggested Payment} = \text{R}464.37 \times 6$$ $$\text{Consultant's Suggested Payment} = \text{R}2\,786.22$$

Since R3 371.224 $\neq$ R2 786.22, the consultant's statement is not valid. Sipho needs to pay more than the consultant suggested.

The total tax that should be deducted for all commissions is given as R14 651.67.
First, calculate the total commission received:

$$\text{Total Commission} = \text{R}15\,260.00 + \text{R}17\,815.00 + \text{R}34\,078.00$$ $$\text{Total Commission} = \text{R}67\,153.00$$

The August 2026 commission is R34 078.00.
To find the tax for the August commission, we use the proportion of the August commission to the total commission.

$$\text{Tax for August Commission} = \left( \frac{\text{August Commission}}{\text{Total Commission}} \right) \times \text{Total Tax on Commissions}$$ $$\text{Tax for August Commission} = \left( \frac{\text{R}34\,078.00}{\text{R}67\,153.00} \right) \times \text{R}14\,651.67$$ $$\text{Tax for August Commission} \approx 0.50744 \times \text{R}14\,651.67$$ $$\text{Tax for August Commission} \approx \text{R}7\,434.99$$

Final Answers:

a) The gross annual income (A) is $\boxed{\text{R}585\,924.40}$.

b) The consultant's statement is ❌ Incorrect. Sipho's remaining tax due is R3 371.22, while the consultant suggested R2 786.22.

c) The amount of tax that should be deducted for the August 2026 commission is $\boxed{\text{R}7\,434.99}$.