Diet Critique and Question

I been cutting down to a decent weight to see my abs. I think I need to lose about 5 more lbs of FAT to see the full effect. Here are my stats and diet:

I'm 5'8 155lbs, maybe about 12%BF.

Bench: 275
Squat: 295
Deads: 275

Meal 1:
40g of whey
2 tbsp natural PB

Meal 2:
1/2 cup oatmeal
1 can of tuna
1 serving of broccoli

Meal 3:
40g of whey
2tbsp PB

Workout

Meal 4:
20-40g of whey
40-80g of sugar, Gatorade or dextrose

Meal 5:
1/2 cup - 1 cup of white rice
20g of chicken

Meal 6:
1 can of tuna
1 serving of flax

Meal 7:
20g whey
1tbsp flax

I been using this diet to cut. Now my questions when I transition to bulk is:

Why do people change their diet drastically, wouldnt it be optimal to just eat the same, just more amounts of it?

And also, some days I cant eat the oatmeal because i forget or dont have the opportunity, but i buy a 6" sub from Subway on wheat, oven roasted chicken breast double meat with tons of veggies, is this acceptable? Is bread GI significantly higher than oatmeal?

Please critique and let me know if theres anything i can improve on?

I think when I bulk I would like to add more solid food for a couple of those shakes possibly...

Do you do cardio?

When do you weight train?

Etc.

~SC~

Yes I do cardio 30-45 minutes before breakfast 4 times a week.

I do weights around 6 PM, my split:

M: Chest/Bis
T: Legs
W: Off
R: Shoulders/Tris
F: Back/Traps
Sat/Sun: Off


My weight training consists of pyramid, 3-4 sets constantly going heavier doing 8 reps max.

Chest:
-Incline DB
-Decline Bench Press
-DB Flat Bench
- Cable cross overs

Bis:
-Straight bar curls
-Preacher curls
-Incline db curls, or just regular dumbbell curls

Legs:
-Squats
-Lunges or Leg Press
-SLDL
-Some sort of calf work

Shoulders:
-DB Presses or hang cleans
-Side or front DB raises
- Side or back DB raises, depending if I did front or side beforehand

Tris:
-Skullcrushers or close grips
-The excercise where u use 2 hands and put a single DB behind your head and lift it up against gravity or dips
-Cable pull downs

Back:
-Close grip rows or pull ups
-Deadlifts
-Lat pulldowns or Single handed DB pulls depend on whethere I did rows or pullups
-One final row movement

Traps:
-DB shurgs or close grip Barbell pulls to the chin

Abs:
I am a believer in doing them everyday I do weights. This is the only muscle where I go for extremely high reps with little weights.

your diet has too many liquid meals freind, get some more solid food for your protein sourcers


DCB

the transition from a cut diet to a bulk diet isn't all that difficult and complicated bro..you would do fine to just continue with the food you used for cutting..but just in higher amounts..