I think I found the answer on the FINCEN website. Here is what I found:
It looks to me the 100,000 peso purchase would not be entered onto the CTR because using the current day's exchange rate i saw of $.076 would only amount to $7,600 and thus be under the $10,000 reporting threshold.
1. What should be entered in items 26 and 27?
If cash received totals over $10,000, enter the total amount of cash received in item 26 (“Total cash in”). If cash disbursed totals over $10,000, enter the total amount of cash disbursed in item 27 (“Total cash out”). Always enter the total dollar amount in items 26 and 27 using the U.S. dollar equivalent. If foreign currency is involved as part of the transaction, use the current business day’s exchange rate to determine the total amount in U.S. currency to enter.
“Cash-in” and “Cash-out” transactions should be considered separately, and not aggregated. However, they may be reported on a single CTR by using both items 26 and 27. (See example three and four in the CTR Instructions, or on the FinCEN web site at
http://www.fincen.gov/fin104_ctr.pdf). If there is a currency exchange, it should be aggregated separately with each of the cash in and cash out totals. Since the currency exchange was one of the transactions that caused the CTR to be created, the bank must mark the “Currency Exchange(s)” box in item 33. In addition, with respect to the currency deposit or withdrawal the bank must mark the box for “Deposit(s)/Withdrawal(s)” in item 34, and the box for “Account Number(s) Affected (if any)” in item 35. Finally, the bank must disclose in item 35 the number of the savings or deposit account affected by the withdrawal or deposit.