There is absolutely no reason in increase his breastmilk amounts. Breastmilk, unlike formula, grows and changes with your baby. The amount of breastmilk needed by a baby is NOT determined by the age/weight like you would with formula. Rather, a good rule of thumb is to give the baby 1 oz/hour of milk. You do NOT calculate breastmilk needs the same way you do formula needs. Remember, you should still be using the newborn sized nipple. You never need to change nipple sizes with your breastfed baby's bottles as it can lead to overeating and premature weaning.
Here's some more info: http://www.kellymom.com/bf/pumping/milkcalc.html
Here's information for your caregiver on how to bottle-feed a breastfed baby: http://www.kellymom.com/bf/pumping/bottle-feeding.html
Does he seem to be guzzling down his bottles? Here's some info on that:
When babies are young, and we first intro the bottle, the bottle goes in the baby's mouth the mouth fills with milk, the baby is obligated to swallow and the action of swallowing initiates another suck. The suck again fills the mouth and the cycle repeats, giving an appearance of the baby "gulping the bottle down hungrily". Many times the baby fusses/cries after the bottle is taken away, leading caregivers or parents to assume that baby isn't "satisfied" with the amount of milk in the bottle. The problem isn't usually the volume of milk but rather the natural desire to "complete" the nursing cycle which at the breast, would include some comfort nursing. Comfort nursing is impossible with the bottle.
As time goes on and because the milk can be seen and measured, it is not unusual that babies are encouraged to feed beyond being full (to "satisfy" the baby). This then creates a situation where the infant is used to feeling over full meaning they then consume the higher volume without complaint, resulting in overfeeding that is only seen in bottle fed infants. Current/ongoing research seems to indicate this is one of the reasons that bottle fed infants are more likely to become obese - they lose their ability to regulate their appetite because they need to eat more as children/teens/adults to feel full.
Of course, milk is supply/demand. At 10 months, if you are able to produce enough to send 3 5 oz bottles, that's probably fine. It's an indication that on the weekend he is "demanding" more from the breast when he nurses. If you are really struggling to keep up with those 5 oz, you would probably even be fine to cut back a little bit and very gradually.
Here's some good info on combining solids and breastfeeding: http://www.mother-2-mother.com/samplemenus.htm
Remember to always offer the bottle/breast before feeding solids and the baby's primary nutrition before 1 yr should be breastmilk/formula. Food at this age is mostly for play and exploration.
Good luck!