In case of pulse dialling the pulses are auto generatied by a traditional mechanical make and break contact of the line or the Dialling IC in modern phones. Still the pulsing time will vary between the two systems. as the delay in mechanical system will depend on the winding sping and the speed in the IC is set by the external and the oscillating components. After all there will be a certain time set by the exchange to detect an error is the delay between two pulses are different.
In tone mode, the tone will be generated almost instantly as the key is pressed and it depend on the persons operating capabilities to dial different number. For Eg, if I can dial a 12 digit number in 3-4 seconds, my "Gardener" will naturally take 12-15 seconds depending on his operating capabilities. Still the dialling speed will be faster if you alreday know the number.. For Eg : Your own number... We usually see/ get such logic less questions in Indian education system. Its all our fate my friend. Cheers