Ashleigh - As I've said previously, October sown seed will give you flowers around mid-May, those sown in the spring will flower in July. To flip it, October sown plants will finish flowering in late-August, whereas spring sown plants will continue until the first frosts.....a mixture (if possible) of both is the best option.
I wouldn't pay too much attention to my 10c temperature figure, as I give it as a rough guide to what is needed for successful germination....as you know, all seeds need a certain amount of warmth to germinate.
Be assured, I don't walk around with a thermometer in my pocket after gardening for more years than I care to remember, I act according to what I see around me. Regarding sowing outdoors, a good rule of thumb would be to keep your eye on your lawn, when it starts to grow & needs cutting would be a good time to sow your SP seeds in-situ......certainly don't go to the trouble of bubble-wrapping etc.