Tax on SAYE company share scheme

My company have an approved save as you earn share scheme in operation. As far as I can figure out when the options are granted the tax situation is:

Say
option to buy share at price of €50 discounted from €60
cost/price at time option is exercised is €80
shares are sold for €90 at some later date

then

Pay USC and PRSI on €30 (€80 - €50)
Pay CGT on €40 (€90 - €50)

Is this right?

And when do they have to paid? USC and PRSI at the end of the savings period and CGT when the shares are sold?

Thanks

No income tax on profit from exercise of grant (80-50) but you will be liable to PRSI and USC. CGT on 90-80.

SAYE are great schemes and really work. If the share price hasn't gone up you don't exercise your option and get your cash back.