What are the advantages in using 2 identical capacitors? What advantage might there be in  using two identical capacitors in  parallel connected in  series with another identical parallel pair, rather than using a single capacitor?
 A: Capacitors are sometimes connected in series to increase the working voltage range, but it is not a good design technique because variances in capacitors can cause a variance in voltage and thus exceed the voltage rating on one of the capacitors.  
And if you can't achieve a value of capacitance with one capacitor, sometimes putting two larger ones in series you can get the desired value.  This might also be the reason a for the odd combination of values and topology.
If you gave us the actual circuit and some information about the application we might be able to provide some more insight.
A: The resultant capacitance of capacitors in parallel is the summation of the capacitances:
$$C_{eq} = \Sigma C$$
While, the inverse of the resultant capacitance of capacitors in series is the summation of their inverses:
$$\frac{1}{C_{eq}} = \Sigma\frac{1}{C}$$
Connecting capacitors in parallel will therefore help in increasing the capacitance of the circuit.

If each capacitor has a capacitance of $C$, your circuit will give a resultant capacitance of:
$$\frac{1}{C_{eq}} = \frac{1}{C+C} + \frac{1}{C+C}$$
$$= \frac{2}{2C}$$
$$= \frac{1}{C}$$
$$\therefore C_{eq} = C$$
