oscilloscope time charging different from the math
As drawn R4 and R3 are in series making the equivalent charging resistor 

\$ R = \frac{1.62 \cdot 1.78}{1.62 + 1.78} + 1.82 + 2.43 = 5.098 k\Omega\$ 

and capacitor

\$ C = \frac{1.4 \cdot 2.2}{1.4 + 2.2} + 1.2 = 2.055 \mu F\$

The time constant is therefore

\$\tau = C \cdot R = 10.47 \text{ ms}\$ 

As pointed out in comments you have neglected R4.  If R4 is only supposed to effect the discharge time it should be connected between the switch and earth.