What do you mean by "sg and og"?
What was your grain bill(names&weights)?
What amount of water did You use for mashing and sparging?
What was your pre boil volume and gravity?
What was your post boil volume and gravity?
If You give us answers of above questions We can help you better. However,It seems that your problem is low EE% (extract efficiency). If your EE% was good and You just had added more water to mash tun, so you could easily increase boil time to achieve right OG and right volume. If the OG (original gravity=post boil gravity) number you've achieved is lower than what recipe had wanted or what You had expected, It is likely due to the low efficiency.This is a common case because the extract efficiency depends on many factors and You must consider them to improve efficiency of your system.Therefore You gain your desired OG as the result of this improvement rather than adding or subtracting water.