Q:

From Puzzling to StackExchange

This is a variation of a game I used to play with my friends in my childhood. You are given a starting word, and using the following operations, you have to reach the target word. The solution that requires the least number of moves wins.
Rules:

In any move, you can either replace a letter, add a letter, remove a letter, split a word or combine two words. These are the five valid moves, and only one of these can be applied in a move.
After each move, each of the resulting words must be valid by itself, even if it makes no sense as a phrase. To level the playing field, only words found on Dictionary.com are considered valid. No proper nouns, abbreviations, prefixes or suffixes allowed. (However, words like jack, john, jane etc. are allowed as they are used as common nouns too.) Alternate spellings and archaic words are permitted, but words referring to specific persons, places or events are not valid.
You may only add a letter to an existing word, but a new letter (such as a or I) cannot create a new word separately. Likewise, you cannot drop a letter from a one-letter word to remove it altogether.

As an example, consider the following solution where I go from stack to exchange:
stack
stark
star
stay
stray
astray
a stray
as stray
ax stray
ex stray
ex stay
ex star
ex stare
ex share
ex chare
ex charge
ex change
exchange 
This solution required 17 moves. (It may not be the optimal strategy for this pair of words, but it is a valid strategy, given just as an example).
Challenge:
In how many moves can you get from Puzzling to Stack Exchange? 
An Extra Twist:
The solution which achieves this in the least number of moves will be awarded the green tick. However, in the event of a tie, each of the words will be assigned their Scrabble score and then added up. The one with the highest Scrabble score will win.
LEADERBOARD: (Only includes valid entries)
User            Moves

Lampost42       20
Gordon K        21
Raystafarian    21

A:

I've got 20

 puzzling 
 muzzling 
 muzz ling 
 fuzz ling 
 fuze ling 
 faze ling 
 fake ling 
 sake ling 
 saker ling 
 sacker ling 
 stacker ling 
 stack er ling 
 stack ex ling 
 stack ex line 
 stack ex lane 
 stack ex cane 
 stack ex care 
 stack ex chare 
 stack ex charge 
 stack ex change 
 stack exchange 

A:

I've done it in 21:

puzzlingmuzzlingmuzz lingmuzz linemuzz lanemuzz canemuzz caremuzz charemuzz chargemuzz changefuzz changefuze changefaze changefare changetare changestare changestarer changestar er changestar ex changestark ex changestark exchangestack exchange

A:

Here's a way to do it in 20 moves:

puzzling
muzzling
mizzling
fizzling
fizz ling
fizz hing
fizz hang
fizz chang
fizz change
fuzz change
fuze change
faze change
fare change
tare change
stare change
starer change
star er change
star ex change
stark ex change
stark exchange
stack exchange

